Charge Transporting Material, Organic Electroluminescent Element, Light Emitting Device, Display Device And Illumination Device

ABSTRACT

[Problem] To provide a charge transporting material which allows for a low driving voltage and is superior in luminous efficiency and durability. 
     [Means for resolution] A charge transporting material comprising a compound represented by any one of the following general formula (1-1) to general formula (1-3): 
     
       
         
         
             
             
         
       
     
     wherein R 111  to R 114 , R 121  to R 125  and R 131  to R 135  each independently represent a hydrogen atom or a substituent, and may be bound together to form a ring; L 111  to L 113  each independently represent O or S; L 121  to L 123  each independently represent a single bond or a divalent linking group; and Ar 111  to Ar 113  each independently represent an aryl group or a heteroaryl group.

FIELD OF THE INVENTION

the present invention relates to a charge transporting material, anorganic electroluminescent element, a light emitting device, a displaydevice and an illumination device.

BACKGROUND OF THE INVENTION

Since organic electroluminescent elements (which may hereinafter also bereferred to as “elements” or “organic EL elements”) are capable ofhigh-luminance light emitting using low voltage driving, they have beenactively researched and developed. The organic electroluminescentelements have a pair of electrodes and an organic layer between the pairof electrodes, and utilize, for light emitting, energy of the excitongenerated as a result of recombination of the electron injected from thecathode and the hole injected from the anode in the organic layer.

In recent years, by using phosphorescence emitting materials, elementsare being enhanced in efficiency. Patent Document 1 discloses a chargetransporting material having a site of a fused ring structure derivedfrom triarylamine, for decreasing driving voltage and enhancingefficiency and durability. Patent Document 2 discloses a chargetransporting material having a site of a fused ring structure derivedfrom triarylamine, for decreasing driving voltage and enhancingefficiency.

RELATED ART DOCUMENT Patent Document

-   [Patent Document 1] WO 2011/042107-   [Patent Document 2] JP-A-2010-050778

SUMMARY OF THE INVENTION Problem that the Invention is to Solve

On the other hand, development of an organic electroluminescent elementemitting green phosphorescence, among organic electroluminescentelements using phosphorescence emitting materials, has recently beenimportant in application to a full-color display or the like.

The present inventors used a compound disclosed in Patent Documents 1and 2 as a host material of a light emitting layer in an organicelectroluminescent element emitting green phosphorescence to evaluatethe element performance thereof, and as a result, it was revealed thatthe compound disclosed in Patent Document 1 is inferior in the luminousefficiency when it is used for an organic electroluminescent elementemitting green phosphorescence and also has a problem in durability. Itwas also revealed that the element using a compound disclosed in PatentDocument 2 exhibited too high driving voltage or was inferior indurability. That is, the elements obtained using previously reportedcompounds all have had problems of too high driving voltage, lowluminous efficiency, or low durability.

Accordingly, an object of the present invention is to provide an chargetransporting material which allows for a low driving voltage and issuperior in luminous efficiency and durability.

Means for Solving the Problem

As a result of the study of the present inventors, it was found that acharge transporting material can be provided, from which an organicelectroluminescent element that can be driven with a low driving voltageand is superior in luminous efficiency and durability can bemanufactured, by a compound having a structure obtained by allowing atriarylamine to fuse with an —O— or —S— linking group and having asubstituent containing an aryl group or a heteroaryl group at apara-position of at least one of the aryl groups of the triarylamine.

The present invention, which is a specific means for solving the aboveproblem, has the following constitution.

[1] A charge transporting material comprising a compound represented byany one of the following general formula (1-1) to general formula (1-3):

[wherein in the general formulae (1-1) to (1-3), R¹¹¹ to R¹¹⁴, R¹²¹ toR¹²⁵ and R¹³¹ to R¹³⁵ each independently represent a hydrogen atom or asubstituent, and may be bound together to form a ring; L¹¹¹ to L¹¹³ eachindependently represent O or S; L¹²¹ to L¹²³ each independentlyrepresent a single bond or a divalent linking group; and Ar¹¹¹ to Ar¹²³each independently represent an aryl group or a heteroaryl group].[2] The charge transporting material described in [1] preferablycomprises a compound represented by the general formula (1-1) or thegeneral formula (1-2).[3] In the charge transporting material described in [1] or [2], it ispreferred that Ar¹¹¹ to Ar¹¹³ in the general formulae (1-1) to (1-3) areeach independently a substituent represented by any one of the followinggeneral formula (2-1) to general formula (2-10):

[wherein in the general formula (2-1) to the general formula (2-10), itis preferred that one of R^(A11) to R^(A15) represents a biding positionto L¹²¹ to L¹²³ in the general formulae (1-1) to (1-3) and the others ofR^(A11) to R^(A15) each independently represent a hydrogen atom or asubstituent; and R^(A21) to R^(A25), R^(A31) to R^(A35), R^(A41) toR^(A45) and R^(A51) to R^(A55) each independently represent a hydrogenatom or a substituent].[4] In the charge transporting material described in [1] or [2], it ispreferred that Ar¹¹¹ to Ar¹¹³ in the general formulae (1-1) to (1-3) areeach independently a substituent represented by any one of the followinggeneral formula (3-1) to general formula (3-3):

[wherein in the general formulae (3-1) to (3-3), * represents a bindingposition to L¹²¹ to L¹²³ in the general formulae (1-1) to (1-3); andR³¹¹, R³¹², R³²¹ to R³²⁵ and R³³¹ to R³³⁵ each independently represent ahydrogen atom or a substituent].[5] In the charge transporting material described in [1] or [2], it ispreferred that Ar¹¹¹ in the general formula (1-1) is a substituentrepresented by the following general formula (4-1):

[wherein in the general formula (4-1), * represents a binding positionto L¹²¹ in the general formula (1-1); and R⁴¹¹ to R⁴¹⁴ and R⁴²¹ to R⁴²⁵each independently represent a hydrogen atom or a substituent].[6] In the charge transporting material described in any one of [1] to[5], it is preferred that at least one of L¹²¹ to L¹²³ and Ar¹²³ toAr¹¹³ in the general formulae (1-1) to (1-3) contains an m-phenylenegroup.[7] An organic electroluminescent element comprising a substrate; a pairof electrodes including an anode and a cathode, disposed on thesubstrate; and an organic layer disposed between the electrodes,characterized in that the organic layer contains the charge transportingmaterial described in any one of [1] to [6].[8] In the organic electroluminescent element described in [7], it ispreferred that the organic layer includes a light emitting layercontaining a phosphorescence emitting material.[9] In the organic electroluminescent element described in [8], it ispreferred that the light emitting layer contains the compoundrepresented by any one of the general formula (1-1) to the generalformula (1-3).[10] In the organic electroluminescent element described in [8] or [9],it is preferred that an Ir complex represented by the following generalformula (E-1) is used in the light emitting layer as the phosphorescenceemitting material:

[wherein in the general formula (E-1), Z¹ and Z² each represent a carbonatom or a nitrogen atom; A¹ represents an atomic group which togetherwith Z¹ and a nitrogen atom forms a 5- or 6-membered hetero ring; B¹represents an atomic group which together with Z² and a carbon atomforms a 5- or 6-membered ring; Z¹ and Z² each independently represent acarbon atom or a nitrogen atom; (X—Y) represents a mono-anionicbidentate ligand; and n_(E1) represents an integer of 1 to 3].[11] In the organic electroluminescent element described in [10], the Ircomplex represented by the general formula (E-1) is preferablyrepresented by the following general formula (E-2):

[wherein in the general formula (E-2), A^(E1) to A^(E8) eachindependently represent a nitrogen atom or C—R^(E); R^(E) represents ahydrogen atom or a substituent; (X—Y) represents a mono-anionicbidentate ligand; and n_(E2) represents an integer of 1 to 3].[12] A light emitting device characterized by comprising the organicelectroluminescent element described in any one of [1] to [11].[13] A display device characterized by comprising the organicelectroluminescent element described in any one of [1] to [11].[14] An illumination device characterized by comprising the organicelectroluminescent element described in any one of [1] to [11].

Advantage of the Invention

According to the present invention, a charge transporting material canbe provided which allows for a low driving voltage, and is superior inluminous efficiency and durability. In addition, by the chargetransporting material according to the present invention, an organicelectroluminescent element can be provided which can be driven with alow driving voltage, and is superior in luminous efficiency anddurability.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 It is a schematic view showing one example of a configuration ofthe organic electroluminescent element according to the presentinvention.

FIG. 2 It is a schematic view showing one example of the light emittingdevice according to the present invention.

FIG. 3 It is a schematic view showing one example of the illuminationdevice according to the present invention.

MODE FOR CARRYING OUT THE INVENTION

Details of the present invention are hereunder described. Thedescription of the configuration requirements below may be based onrepresentative embodiments of the present invention, but the presentinvention is not limited to these embodiments. Incidentally, in thepresent specification, the range expressed with “to” means a rangeincluding the numerical values before and after “to” as the lower limitand the upper limit, respectively.

[Charge Transporting Material]

The charge transporting material according to the present invention ischaracterized by comprising a compound represented by any one of thefollowing general formula (1-1) to general formula (1-3):

[wherein in the general formulae (1-1) to (1-3), R¹¹¹ to R¹¹⁴, R¹²¹ toR¹²⁵ and R¹³¹ to R¹³⁵ each independently represent a hydrogen atom or asubstituent, and may be bound together to form a ring; L¹¹¹ to L¹¹³ eachindependently represent O or S; L¹²¹ to L¹²³ each independentlyrepresent a single bond or a divalent linking group; and Ar¹¹¹ to Ar¹¹³each independently represent an aryl group or a heteroaryl group].

Although not wishing to be bound by any theory, such a constitution ofthe compound of the present invention makes it possible to provide ahigh luminous efficiency as well as a low voltage and enhanceddurability when the compound is used as a material for an organicelectroluminescent element. The durability can be enhanced byintroducing a structure obtained by allowing triphenylamine to fuse withan oxygen atom or a sulfur atom, and in addition, by making the highlyelectron-accepting group represented by Ar¹¹¹ to Ar¹¹³ have a specificstructure. This is believed to be due to stabilization of HOMO,suppression of cleavage of N-phenyl bonds in the triarylamine where theHOMO distributes, and protection of the reactive point of the site wherethe LUMO distributes. The lower voltage is assumed to be caused bydecrease of the ionization potential (and increase of the electronaffinity).

The charge transporting material represented by any one of the generalformula (1-1) to the general formula (1-3) can be preferably used fororganic electronic elements such as an electrophotography, an organictransistor, an organic photoelectric transducer (for energy conversion,a sensor, or other applications), and an organic electroluminescentelement, and especially preferably used for an organicelectroluminescent element.

The charge transporting material according to the present invention canbe used for a thin film containing the compound represented any one ofthe general formula (1-1) to the general formula (1-3). The thin filmcan be formed by a dry film forming method such as a vapor depositionmethod, a sputtering method, etc. or a wet film forming method such as atransfer method, a printing method, etc. by using the composition. Thethin film may have any film thickness depending on the use thereof, andthe thickness is preferably 0.1 nm to 1 mm, more preferably 0.5 nm to 1μm, still more preferably 1 nm to 200 nm, and especially preferably 1 nmto 100 nm.

A preferred range of the charge transporting material including thecompound represented by any of the general formula (1-1) to the generalformula (1-3) is hereinunder described.

In the present invention, hydrogen atoms in the description of thegeneral formula (1-1) to the general formula (1-3) or the other generalformulae indicate to include isotopes (deuterium or the like), and atomswhich constitute a further substituent indicate to include isotopesthereof.

In the present invention, a “substituent” means that the substituent maybe further substituted. For example, when an “alkyl group” is mentionedin the present invention, the alkyl group includes an alkyl groupsubstituted with fluorine atoms (such as a trifluoromethyl group), analkyl group substituted with aryl groups (such as a triphenylmethylgroup), or the like. When an “alkyl group having 1 to 6 carbon atoms” ismentioned, however, the phrase means that the carbon number of the wholegroup including all substituents is 1 to 6.

In the general formula (1-1) to the general formula (1-3), R¹¹¹ to R¹¹⁴,R¹²¹ to R¹²⁵ and R¹³¹ to R¹³⁵ each independently represent a hydrogenatom or a substituent, and may be bound together to form a ring.

In the general formula (1-1) to the general formula (1-3), thesubstituent represented by R¹¹¹ to R¹¹⁴ include, but is not particularlylimited to, groups represented by the following Substituent Group A.

<<Substituent Group A>>

An alkyl group (having preferably from 1 to 30 carbon atoms, morepreferably from 1 to 20 carbon atoms, and especially preferably from 1to 10 carbon atoms; for example, methyl, ethyl, n-propyl, isopropyl,t-butyl, n-hexyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl,cyclopentyl, cyclohexyl, and a trifluoromethyl group), an alkenyl group(having preferably from 2 to 30 carbon atoms, more preferably from 2 to20 carbon atoms, and especially preferably from 2 to 10 carbon atoms;for example, vinyl, allyl, 2-butenyl, and 3-pentenyl), an alkynyl group(having preferably from 2 to 30 carbon atoms, more preferably from 2 to20 carbon atoms, and especially preferably from 2 to 10 carbon atoms;for example, propargyl, and 3-pentynyl), an aryl group (havingpreferably from 6 to 30 carbon atoms, more preferably from 6 to 20carbon atoms, and especially preferably from 6 to 14 carbon atoms; forexample, phenyl, p-methylphenyl, a 2-fluorophenyl group, a3-fluorophenyl group, a 4-fluorophenyl group, naphthyl, anthranyl, andtriphenylenyl), an amino group (having preferably from 0 to 30 carbonatoms, more preferably from 0 to 20 carbon atoms, and especiallypreferably from 0 to 10 carbon atoms; for example, amino, methylamino,dimethylamino, diethylamino, dibenzylamino, phenylamino, diphenylamino,and ditolylamino), an alkoxy group (having preferably from 1 to 30carbon atoms, more preferably from 1 to 20 carbon atoms, and especiallypreferably from 1 to 10 carbon atoms; for example, methoxy, ethoxy,butoxy, and 2-ethylhexyloxy), an aryloxy group (having preferably from 6to 30 carbon atoms, more preferably from 6 to 20 carbon atoms, andespecially preferably from 6 to 12 carbon atoms; for example, phenyloxy,1-naphthyloxy, and 2-naphthyloxy), a heterocyclic oxy group (havingpreferably from 1 to 30 carbon atoms, more preferably from 1 to 20carbon atoms, and especially preferably from 1 to 12 carbon atoms; forexample, pyridyloxy, pyrazyloxy, pyrimidyloxy, and quinolyloxy), an acylgroup (having preferably from 2 to 30 carbon atoms, more preferably from2 to 20 carbon atoms, and especially preferably from 2 to 12 carbonatoms; for example, acetyl, benzoyl, formyl, and pivaloyl), analkoxycarbonyl group (having preferably from 2 to 30 carbon atoms, morepreferably from 2 to 20 carbon atoms, and especially preferably from 2to carbon atoms; for example, methoxycarbonyl, and ethoxycarbonyl), anaryloxycarbonyl group (having preferably from 7 to 30 carbon atoms, morepreferably from 7 to 20 carbon atoms, and especially preferably from 7to 12 carbon atoms; for example, phenyloxycarbonyl), an acyloxy group(having preferably from 2 to 30 carbon atoms, more preferably from 2 to20 carbon atoms, and especially preferably from 2 to 10 carbon atoms;for example, acetoxy and benzoyloxy), an acylamino group (havingpreferably from 2 to 30 carbon atoms, more preferably from 2 to 20carbon atoms, and especially preferably from 2 to 10 carbon atoms; forexample, acetylamino and benzoylamino), an alkoxycarbonylamino group(having preferably from 2 to 30 carbon atoms, more preferably from 2 to20 carbon atoms, and especially preferably from 2 to 12 carbon atoms;for example, methoxycarbonylamino), an aryloxycarbonylamino group(having preferably from 7 to 30 carbon atoms, more preferably from 7 to20 carbon atoms, and especially preferably from 7 to 12 carbon atoms;for example, phenyloxycarbonylamino), a sulfonylamino group (havingpreferably from 1 to 30 carbon atoms, more preferably from 1 to 20carbon atoms, and especially preferably from 1 to 12 carbon atoms; forexample, methanesulfonylamino and benzenesulfonylamino), a sulfamoylgroup (having preferably from 0 to 30 carbon atoms, more preferably from0 to 20 carbon atoms, and especially preferably from 0 to 12 carbonatoms; for example, sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, andphenylsulfamoyl), a carbamoyl group (having preferably from 1 to 30carbon atoms, more preferably from 1 to 20 carbon atoms, and especiallypreferably from 1 to 12 carbon atoms; for example, carbamoyl,methylcarbamoyl, diethylcarbamoyl, and phenylcarbamoyl), an alkylthiogroup (having preferably from 1 to 30 carbon atoms, more preferably from1 to 20 carbon atoms, and especially preferably from 1 to 12 carbonatoms; for example, methylthio and ethylthio), an arylthio group (havingpreferably from 6 to 30 carbon atoms, more preferably from 6 to 20carbon atoms, and especially preferably from 6 to 12 carbon atoms; forexample, phenylthio), a heterocyclic thio group (having preferably from1 to 30 carbon atoms, more preferably from 1 to 20 carbon atoms, andespecially preferably from 1 to 12 carbon atoms; for example,pyridylthio, 2-benzimizolylthio, 2-benzoxazolylthio, and2-benzthiazolylthio), a sulfonyl group (having preferably from 1 to 30carbon atoms, more preferably from 1 to 20 carbon atoms, and especiallypreferably from 1 to 12 carbon atoms; for example, mesyl and tosyl), asulfinyl group (having preferably from 1 to 30 carbon atoms, morepreferably from 1 to 20 carbon atoms, and especially preferably from 1to 12 carbon atoms; for example, methane sulfinyl and benzene sulfinyl),a ureido group (having preferably from 1 to 30 carbon atoms, morepreferably from 1 to 20 carbon atoms, and especially preferably from 1to 12 carbon atoms; for example, ureido, methylureido, andphenylureido), a phosphoric amide group (having preferably from 1 to 30carbon atoms, more preferably from 1 to 20 carbon atoms, and especiallypreferably from 1 to 12 carbon atoms; for example, diethylphosphoricamide and phenylphosphoric amide), a hydroxyl group, a mercapto group, ahalogen atom (for example, a fluorine atom, a chlorine atom, a bromineatom, and an iodine atom), a sulfo group, a carboxyl group, a nitrogroup, a hydroxamic acid group, a sulfino group, a hydrazino group, animino group, a heterocyclic group (inclusive of an aromatic heterocyclicgroup, which has preferably from 1 to 30 carbon atoms, and morepreferably from 1 to 12 carbon atoms and in which examples of the heteroatom include a nitrogen atom, an oxygen atom, a sulfur atom, aphosphorus atom, a silicon atom, a selenium atom, and a tellurium atom;and specific examples thereof include pyridyl, pyrazinyl, pyrimidyl,pyridazinyl, pyrrolyl, pyrazolyl, triazolyl, imidazolyl, oxazolyl,triazolyl, isoxazolyl, isothiazolyl, quinolyl, furyl, thienyl,selenophenyl, tellurophenyl, piperidyl, piperidino, morpholino,pyrrolidyl, pyrrolidino, benzoxazolyl, benzimidazolyl, benzothiazolyl, acarbazolyl group, an azepinyl group, a silolyl group, adibenzothiophenyl group and a dibenzofuranyl group), a silyl group(having preferably from 3 to 40 carbon atoms, more preferably from 3 to30 carbon atoms, and especially preferably from 3 to 24 carbon atoms;for example, trimethylsilyl, and triphenylsilyl), a silyloxy group(having preferably from 3 to 40 carbon atoms, more preferably from 3 to30 carbon atoms, and especially preferably from 3 to 24 carbon atoms;for example, trimethylsilyloxy and triphenylsilyloxy), and a phosphorylgroup (for example, a diphenylphosphoryl group and a dimethylphosphorylgroup). These substituents may be further substituted, and examples ofthe further substituent include groups selected from the SubstituentGroup A as described above.

The substituent on a carbon atom is preferably an alkyl group, aperfluoroalkyl group, an aryl group, a heteroaryl group, a dialkylaminogroup, a diarylamino group, an alkoxy group, a cyano group, or afluorine atom, more preferably an alkyl group or an aryl group, andespecially preferably a methyl group or a phenyl group.

Preferably, R¹¹¹ and R¹³⁵ are each independently a hydrogen atom orbound to each other to form a ring, and more preferably a hydrogen atom.

R¹¹² and R¹¹³ are preferably each independently a hydrogen atom or analkyl group, and more preferably are both hydrogen atoms.

Preferably, R¹¹⁴ and R¹²¹ are each independently a hydrogen atom orbound to each other to form a ring, and more preferably a hydrogen atom.

R¹²² to R¹²⁴ are preferably each independently a hydrogen atom, an alkylgroup or an aryl group, more preferably a hydrogen atom or an arylgroup, and especially preferably are all hydrogen atoms.

Preferably, R¹²⁵ and R¹³¹ are each independently a hydrogen atom orbound to each other to form a ring, and more preferably a hydrogen atom.

R¹³² to R¹³⁴ are preferably each independently a hydrogen atom, an alkylgroup or an aryl group, more preferably a hydrogen atom or an arylgroup, and especially preferably are all hydrogen atoms.

Preferred ranges of the substituents represented by R¹¹¹ to R¹¹⁴, R¹²¹to R¹²⁵ and R¹³¹ to R¹³⁵ are the same as the preferred ranges of therespective substituents in the Substituent Group A.

When two of R¹¹¹ to R¹¹⁴, R¹²¹ to R¹²⁵ and R¹³¹ to R¹³⁵ are bound toeach other to form a ring, the carbon atoms on which the respectivesubstituents are substituted are preferably connected to each other viaa single bond, O, S, CR⁵¹¹R⁵¹², NR⁵¹³, or SiR⁵¹⁴R⁵¹⁵ (R⁵¹¹ to R⁵¹⁵ eachindependently represent a hydrogen atom or a substituent), morepreferably connected via a single bond, O or S, especially preferablyconnected via O or S, and further especially preferably connected via O.

Examples of the substituents represented by R⁵¹¹ and R⁵¹², which aresubstituents on a carbon atom, include the Substituent Group A mentionedabove.

Examples of the substituent represented by R⁵¹³, which is a substituenton a nitrogen atom, include the following Substituent Group B.

<<Substituent Group B>>

An alkyl group (having preferably from 1 to 30 carbon atoms, morepreferably from 1 to 20 carbon atoms, and especially preferably from 1to 10 carbon atoms; for example, methyl, ethyl, isopropyl, t-butyl,n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, andcyclohexyl), an alkenyl group (having preferably from 2 to 30 carbonatoms, more preferably from 2 to 20 carbon atoms, and especiallypreferably from 2 to 10 carbon atoms; for example, vinyl, allyl,2-butenyl, and 3-pentenyl), an alkynyl group (having preferably from 2to 30 carbon atoms, more preferably from 2 to 20 carbon atoms, andespecially preferably from 2 to 10 carbon atoms; for example, propargyland 3-pentynyl), an aryl group (having preferably from 6 to 30 carbonatoms, more preferably from 6 to 20 carbon atoms, and especiallypreferably from 6 to 12 carbon atoms; for example, phenyl,p-methylphenyl, naphthyl, and anthranyl), a cyano group, and aheterocyclic group (inclusive of an aromatic heterocyclic group, whichhas preferably from 1 to 30 carbon atoms, and more preferably from 1 to12 carbon atoms and in which examples of the hetero atom include anitrogen atom, an oxygen atom, a sulfur atom, a phosphorus atom, asilicon atom, a selenium atom, and a tellurium atom; and specificexamples thereof include pyridyl, pyrazinyl, pyrimidyl, pyridazinyl,pyrrolyl, pyrazolyl, triazolyl, imidazolyl, oxazolyl, triazolyl,isoxazolyl, isothiazolyl, quinolyl, furyl, thienyl, selenophenyl,tellurophenyl, piperidyl, piperidino, morpholino, pyrrolidyl,pyrrolidino, benzoxazolyl, benzimidazolyl, benzothiazolyl, a carbazolylgroup, an azepinyl group, and a silolyl group). These substituents maybe further substituted, and examples of the further substituent includegroups selected from the Substituent Group B as described above.

The substituent on a nitrogen atom represented by R⁵¹³ is preferably analkyl group, an aryl group, and an aromatic heterocyclic group, morepreferably an aryl group, and especially preferably a phenyl group or aphenyl group substituted with a phenyl group (biphenyl group).

Preferred ranges of the substituents represented by R⁵¹⁴ and R⁵¹⁵, whichare substituents on a silicon atom, are the same as the preferred rangesof the substituents represented by R⁵¹¹ and R⁵¹², which are substituentson a carbon atom.

In the general formula (1-1) to the general formula (1-3), L¹¹¹ to L¹¹³each independently represent O or S, and preferably O.

In the general formula (1-1) to the general formula (1-3), L¹²¹ to L¹²³each independently represent a single bond or a divalent linking group.L¹²¹ to L¹²³ preferably each independently represent a single bond,phenylene group, a biphenylene group, an m-terphenylene group, ap-terphenylene group, —N(Ar′)— (wherein, Ar′ represents an aryl group,and a preferred range thereof is the same as the preferred range of thearyl group represented by Ar¹¹¹ to Ar¹¹³), more preferably represent asingle bond, a phenylene group, a biphenylene group, an m-terphenylenegroup or a p-terphenylene group, still more preferably a single bond, aphenylene group or biphenylene group, and especially preferably a singlebond or phenylene group. When L¹²¹ to L¹²³ each are a phenylene group,the phenylene group may be substituted with an amino group to form aphenyleneamino group, and Ar¹²³ to Ar¹¹³ may be bound to this aminogroup. Such a material is preferred as a hole transporting material.

In addition, it is preferred to introduce a meta-linking phenylenegroup, biphenylene group or terphenylene group as at least one of L¹²¹to L¹²³ and after-mentioned Ar¹²³ to Ar¹¹³, from the viewpoint ofcapability of reducing the overlapping of HOMO and LUMO, and therebysuppressing deterioration of the excited triplet state, resulting inmaking it possible for a green phosphorescence emitting material to emitlight efficiently. It is more preferred that at least one of L¹²¹ toL¹²³ and Ar¹¹¹ to Ar¹¹³ contains an m-phenylene group.

In the general formula (1-1) to the general formula (1-3), Ar¹¹¹ toAr¹¹³ each independently represent an aryl group or a heteroaryl group,and from the viewpoint of durability, an aryl group is preferred.

An aryl group represented by each of Ar¹¹¹ to Ar¹¹³ is preferably anaryl group having 6 to 30 carbon atoms, more preferably an aryl grouphaving 6 to 20 carbon atoms, and especially preferably a phenyl group.

A heteroaryl group represented by each of Ar¹¹¹ to Ar¹¹³ is preferably aheteroaryl group having 5 to 6 ring members, more preferably aheteroaryl group having 6 ring members, and especially preferably atriazyl group having 6 ring members. The hetero atoms constituting theheteroaryl group represented by Ar¹¹¹ to Ar¹¹³ have no particularlimitation, but it is preferred that a nitrogen atom is containedtherein. Among them, the heteroaryl group represented by Ar¹¹¹ to Ar¹¹³is especially preferably a pyridyl group, a pyrimidyl group, or atriazyl group, and more especially preferably a triazyl group.

Ar¹¹¹ to Ar¹¹³ may have a further substituent, and examples of thesubstituent include groups represented by the Substituent Group Amentioned above, and the substituent is preferably an alkyl group, anaryl group, a cyano group, or —SiR^(A61)R^(A62)R^(A63) (R^(A61),R^(A62), and R^(A63) each independently represent a hydrogen atom or asubstituent, and examples of the substituent include groups representedby the Substituent Group A mentioned below. The substituent ispreferably a hydrogen atom, an alkyl group, a cyano group or an arylgroup, and more preferably a hydrogen atom, a cyano group or an arylgroup, and especially preferably a hydrogen atom, a cyano group or anaryl group), and more preferably an aryl group or a cyano group, andespecially preferably the substituent has at least one cyano group.

The further substituent on Ar¹¹¹ to Ar¹¹³ may have a furthersubstituent, and examples of the substituent include the same group asthe further substituent on Ar¹¹¹ to Ar¹¹³ or groups obtained by removingAr¹¹¹ to Ar¹¹³ respectively from the compounds represented by thegeneral formula (1-1) to the general formula (1-3).

In the charge transporting material according to the present invention,it is preferred that Ar¹¹¹ to Ar¹¹³ in the general formulae (1-1) to(1-3) are each independently a substituent represented by any one of thegeneral formula (2-1) to the general formula (2-10).

In the general formula (2-1) to the general formula (2-10), one ofR^(A11) to R^(A15) represents a binding position to L¹²¹ to L¹²³ in thegeneral formulae (1-1) to (1-3), and the others thereof eachindependently represent a hydrogen atom or a substituent.

Among R^(A11) to R^(A15), the position of the group representing thebinding position to L¹²¹ to L¹²³ in the general formulae (1-1) to (1-3)is not particularly limited, but is preferably at R^(A12) or R^(A14)from the viewpoint of introducing a meta-linking phenylene group,biphenylene group or terphenylene group (preferably a m-phenylene group)into Ar¹¹¹ to Ar¹¹³ to thereby allowing the green phosphorescenceemitting material to emit light efficiently as described before. Thebinding position is more preferably at R^(A12).

In the general formula (2-1) to the general formula (2-10), amongR^(A11) to R^(A15), the groups other than the binding position to L¹²¹to L¹²³ in the general formulae (1-1) to (1-3) each independentlyrepresent a hydrogen atom or a substituent, more preferably a hydrogenatom or a group represented by the Substituent Group A, more preferablya hydrogen atom, an alkyl group, an aryl group or a cyano group,especially preferably a hydrogen atom, an alkyl group or a cyano group,and more especially preferably a hydrogen atom.

In the general formula (2-1) to the general formula (2-10), R^(A21) toR^(A25), R^(A31) to R^(A35), R^(A41) to R^(A45) and R^(A51) to R^(A55)each independently represent a hydrogen atom or a substituent, andexamples of the substituent include groups represented by theSubstituent Group A described above. Among them, the substituent ispreferably a hydrogen atom, an alkyl group, a cyano group or an arylgroup, more preferably a hydrogen atom, a cyano group or an aryl group,especially preferably a hydrogen atom or an aryl group, and especiallypreferably a hydrogen atom.

Among R^(A21) to R^(A25), R^(A31) to R^(A35), R^(A41) to R^(A45) andR^(A51) to R^(A55), it is also preferred that R^(A33) has an aryl groupfrom the viewpoint of forming a p-terphenylene structure to bepreferably combined with the green phosphorescence emitting material.From the viewpoint of the driving voltage and durability, it is alsopreferred that R^(A32) has a group obtained by removing Ar¹¹¹ to Ar¹¹³respectively from the compounds represented by the general formula (1-1)to the general formula (1-3).

In the general formula (2-1) to the general formula (2-10), however, thenumber of cyano group that is substituted on one benzene ring ispreferably 0 to 2, and more preferably 0 or 1, and still morepreferably, the number of benzene ring substituted with a cyano group isone.

In the general formula (2-1) to the general formula (2-10), preferredranges of the substituents represented by R^(A11) to R^(A15), R^(A21) toR^(A25), R^(A31) to R^(A35), R^(A41) to R^(A45) and R^(A51) to R^(A55)are the same as the preferred ranges of the respective substituents inthe description of the Substituent Group A.

Among them, in the charge transporting material according to the presentinvention, the substituents represented by the general formula (2-1) tothe general formula (2-3) and the general formula (2-5) to the generalformula (2-7) are preferred among the substituents represented by thegeneral formula (2-1) to the general formula (2-10), from the viewpointof the driving voltage and durability, and the substituents representedby the general formula (2-1), the general formula (2-2), the generalformula (2-5) and the general formula (2-6) are more especiallypreferred from the viewpoint of the durability.

In the charge transporting material according to the present invention,Ar¹¹¹ to Ar¹¹³ in the general formulae (1-1) to (1-3) are eachindependently a substituent represented by any one of the generalformula (3-1) to the general formula (3-3).

In the general formulae (3-1) to (3-3), * represents a binding positionto L¹²¹ to L¹²³ in the general formulae (1-1) to (1-3).

In the general formulae (3-1) to (3-3), R³¹¹, R³¹², R³²¹ to R³²⁵ andR³³¹ to R³³⁵ each independently represent a hydrogen atom or asubstituent (examples of the substituent include the above-mentionedSubstituent Group A), and more preferably a hydrogen atom or an arylgroup. It is more preferred that at least one of R³²³ and R³³³ is anaryl group and the others are hydrogen atoms.

In the general formulae (3-1) to (3-3), preferred ranges of thesubstituents represented by R³¹¹, R³¹², R³²¹ to R³²⁵ and R³³¹ to R³³⁵are the same as the preferred ranges of the respective substituents inthe description of the Substituent Group A.

In the charge transporting material according to the present invention,the substituent represented by the general formula (3-3) is preferredamong the substituents represented by the general formula (3-1) to thegeneral formula (3-3) from the viewpoint of the driving voltage.

In the charge transporting material according to the present invention,it is also preferred that Ar¹¹¹ in the general formula (1-1) is asubstituent represented by the following general formula (4-1).

In the general formula (4-1), * represents a binding position to L¹²¹ inthe general formula (1-1).

In the general formula (4-1), R⁴¹¹ to R⁴¹⁴ and R⁴²¹ to R⁴²⁵ eachindependently represent a hydrogen atom or a substituent (examples ofthe substituent include the above-mentioned Substituent Group A), andmore preferably a hydrogen atom or an aryl group. It is more preferredthat R⁴²³ is an aryl group and the others are hydrogen atoms.

In the general formula (4-1), preferred ranges of the substituentsrepresented by R⁴¹¹ to R⁴¹⁴ and R⁴²¹ to R⁴²⁵ are the same as thepreferred ranges of the respective substituents in the description ofthe Substituent Group A.

In the charge transporting material according to the present invention,Ar¹¹¹ to Ar¹¹³ in the general formulae (1-1) to (1-3) are preferably thesubstituents represented by the general formulae (2-1) to (2-10) and thegeneral formula (3-3) among the substituents represented by the generalformula (2-1) to the general formula (2-10), the general formula (3-1)to the general formula (3-3) and the general formula (4-1), and morepreferably the substituents represented by the general formula (2-1) tothe general formula (2-3), and the general formula (2-5) to the generalformula (2-7) from the viewpoint of the driving voltage, especiallypreferably the substituents represented by the general formula (2-1) tothe general formula (2-3) and the general formula (2-5) to the generalformula (2-7) from the viewpoint of the durability, and more especiallypreferably the substituents represented by the general formula (2-1),the general formula (2-2), the general formula (2-5) and the generalformula (2-6) from the viewpoint of the durability.

The charge transporting material according to the present inventionpreferably includes a compound represented by the general formula (1-1)or the general formula (1-2) among the compounds represented by any ofthe general formula (1-1) to the general formula (1-3) from theviewpoint of the durability.

When the light emitting material is a phosphorescent material emittinggreen light, in the compounds represented by any of the general formula(1-1) to the general formula (1-3), the number of the single-ringaromatic ring having 6 ring members constituted of carbon atoms ornitrogen atoms that is connected at para-position is preferably not morethan three. For example, when a further single-ring aromatic ring having6 ring members constituted of carbon atoms or nitrogen atoms (such as abenzene ring) is connected to an end of a p-terphenylene groupstructure, the ring is preferably connected at the mete-position. Whenthe light emitting material is a phosphorescence material emitting redlight, the number of the single ring aromatic rings having 6 ringmembers constituted of carbon atoms or nitrogen atoms that is connectedat para-position is preferably not more than 5, and more preferably notmore than 4.

In the case where the compound represented by any one of the generalformula (1-1) to the general formula (1-3) is used further in an organiclayer of an organic electroluminescent element, a more preferredstructure thereof is different depending on which function layer thecompound is used in, among the organic layers. Amore preferred structureof the compound represented by any one of the general formula (1-1) tothe general formula (1-3) will be described later in the description ofthe organic electroluminescent element according to the presentinvention.

When the light emitting material is a phosphorescent material emittinggreen light, the T₁ energy in the film state of the compound representedby any one of the general formula (1-1) to the general formula (1-3) ispreferably 56 kcal/mol to 80 kcal/mol, more preferably 57 kcal/mol to 70kcal/mol, and still more preferably 58 kcal/mol to 66 kcal/mol. When thelight emitting material is a phosphorescent material emitting red light,the T₁ energy in the film state of the compound represented by any oneof the general formula (1-1) to the general formula (1-3) is preferably47 kcal/mol to 80 kcal/mol, more preferably 48 kcal/mol to 70 kcal/mol,and still more preferably 49 kcal/mol to 66 kcal/mol. In particular,when a phosphorescence emitting material is used as the light emittingmaterial, the T₁ energy is preferably within the above range.

By measuring a phosphorescence emission spectrum of a thin film of thematerial, the T₁ energy can be obtained from the end on the shorterwavelength side. For example, a film of the material is formed on acleaned quarts glass substrate in a thickness of about 50 nm by a vacuumvapor deposition method, and a phosphorescence emission spectrum of thethin film is measured using Hitachi spectrofluorometer F-7000 (HitachiHigh-Technologies Corporation) under a temperature of liquid nitrogen.The wavelength at the rising point of the obtained emission spectrum onthe shorter wavelength side is converted to a value of an energy unit,thereby obtaining the T₁ energy.

In the charge transporting material according to the present invention,a molecular weight of the compound represented by any one of the generalformula (1-1) to the general formula (1-3) is preferably 1000 or less,more preferably 500 to 1000, and especially preferably 600 to 900. Thisrange of the molecular weight can provide a material which provides agood film quality and is excellent in suitability to sublimationpurification and vapor deposition. In particular, it is preferred thatthe compound represented by any one of the general formula (1-1) to thegeneral formula (1-3) has a molecular weight of 600 to 1000 from theviewpoint of the suitability to vapor deposition.

From the viewpoint of operating the organic electroluminescent elementstably during driving at a high temperature or stably against the heatgeneration during driving the element, the compound represented by anyone of the general formula (1-1) to the general formula (1-3) preferablyhas a glass transition temperature (Tg) of 80° C. to 400° C., morepreferably 100° C. to 400° C., still more preferably 120° C. to 400° C.

When the purity of the compound represented by any one of the generalformula (1-1) to the general formula (1-3) is low, since the impuritiesmay act as a trap in a charge transport or promote deterioration of theelement, it is preferred that the purity of the compound represented byany one of the general formula (1-1) to the general formula (1-3) is ashigh as possible. The purity can be measured, for example, with a highperformance liquid chromatography (HPLC), and the area ratio of thecompound represented by any one of the general formula (1-1) to thegeneral formula (1-3) when detected at an optical absorption intensityof 254 nm is preferably 99.00% or more, more preferably 99.50% or more,especially preferably 99.90% or more, and most preferably 99.9% or more.

As known in a carbazole-based material disclosed in WO 2008/117889, amaterial of a compound obtained by substituting a part or all ofhydrogen atoms in the compound represented by any one of the generalformula (1-1) to the general formula (1-3) with deuterium atoms can alsobe preferably used as a charge transporting material.

Specific examples of the compound represented by any one of the generalformula (1-1) to the general formula (1-3) are shown below, but thepresent invention is not limited thereto.

The compound represented by any one of the general formula (1-1) to thegeneral formula (1-3) can be synthesized by any method disclosed inJP-A-2007-266598, JP-A-2011-233603, etc., or any combination of theother known reactions.

It is preferred that after the synthesis, the compound is purified bycolumn chromatography, recrystallization, or the like, and thereafterpurified by sublimation purification. By sublimation purification, it ispossible not only to separate organic impurities but also to effectivelyremove the inorganic salts, remaining solvent, or the like.

[Organic Electroluminescent Element]

The organic electroluminescent element according to the presentinvention includes a substrate; a pair of electrodes including an anodeand a cathode, disposed on the substrate; and an organic layer disposedbetween the electrodes, and is characterized in that the organic layercontains at least one compound represented by any one of the generalformula (1-1) to the general formula (1-3).

The configuration of the organic electroluminescent element according tothe present invention is not particularly limited. FIG. 1 shows anexample of the configuration of the organic electroluminescent elementaccording to the present invention. The organic electroluminescentelement 10 in FIG. 1 includes organic layers between a pair ofelectrodes (an anode 3, and a cathode 9) on a substrate 2.

The configuration of the element, the substrate, the anode and thecathode, of the organic electroluminescent element are described indetail, for example, in JP-A-2008-270736, and the matters described inthe patent publication can be applied to the present invention.

Preferred embodiments of the organic electroluminescent elementaccording to the present invention are hereunder described, in the orderof the substrate, electrode, organic layer, protective layer, sealingenclosure, driving method, emission peak wavelength, and applicationthereof.

<Substrate>

The organic electroluminescent element according to the presentinvention has a substrate.

The substrate used in the present invention is preferably a substratethat does not scatter or decay light emitted from the organic layer. Inthe case of an organic material, those having excellent heat resistance,dimensional stability, solvent resistance, electrical insulatingproperties, and processability are preferred.

<Electrodes>

The organic electroluminescent element according to the presentinvention has a pair of electrodes including an anode and a cathode,disposed on the substrate.

In view of the properties of the light emitting element, at least oneelectrode of a pair of electrodes, the anode and the cathode, ispreferably transparent or semi-transparent.

(Anode)

The anode may be usually one having a function as an electrode ofsupplying holes to an organic layer, and is not particularly limited interms of its shape, structure, size, or the like. Further, depending onthe use and purpose of the light emitting element, the anode can besuitably selected from the known electrode materials. As describedabove, the anode is usually provided as a transparent anode.

(Cathode)

The cathode may be usually one having a function as an electrode ofinjecting electrons to an organic layer, and is not particularly limitedin terms of its shape, structure, size, or the like. Further, dependingon the use and purpose of the light emitting element, the cathode can besuitably selected from the known electrode materials.

<Organic Layer>

The organic electroluminescent element according to the presentinvention includes (an) organic layer(s) disposed between theelectrodes, and is characterized by the organic layer(s) containing atleast one compound represented by any one of the general formula (1-1)to the general formula (1-3). The organic layer(s) preferably include(s)a phosphorescence emitting material and the compound represented by anyone of the general formula (1-1) to the general formula (1-3).

The organic layer is not particularly limited, and may be appropriatelyselected according to the intended use and purpose of the organicelectroluminescent element, and is preferably formed on the transparentelectrode or the semi-transparent electrode. In this case, the organiclayer is formed on the whole or a part of the surface of the transparentelectrode or the semi-transparent electrode.

The shape, size and thickness of the organic layer are not particularlylimited, and may be appropriately selected according to the intendedpurpose.

The configuration of the organic layers, the method of forming theorganic layer, preferred aspects of each layer constituting the organiclayers, and the material used in each layer, in the organicelectroluminescent element according to the present invention areexplained in turn bellow.

(Configuration of Organic Layers)

In the organic electroluminescent element according to the presentinvention, the organic layers preferably include a charge transportinglayer.

The charge transporting layer means a layer in which charge transferoccurs when a voltage is applied to the organic electroluminescentelement.

Specifically, examples of the charge transporting layer include a holeinjecting layer, a hole transporting layer, an electron blocking layer,a light emitting layer, a hole blocking layer, an electron transportinglayer and an electron injecting layer. The charge transporting layer ispreferably a hole injecting layer, a hole transporting layer, anelectron blocking layer or a light emitting layer. When a chargetransporting layer formed by a coating method is a hole injecting layer,a hole transporting layer, an electron blocking layer or a lightemitting layer, it becomes possible to manufacture an organicelectroluminescent element of high efficiency with a low cost. Thecharge transporting layer is more preferably a hole injecting layer, ahole transporting layer or an electron blocking layer.

In the organic electroluminescent element according to the presentinvention, however, even when the organic layers include a lightemitting layer and other organic layers, the layers are not alwaysrequired to be clearly distinguished from one another.

In the organic electroluminescent element according to the presentinvention, the organic layers preferably contain a phosphorescenceemitting material and the compound represented by any one of the generalformula (1-1) to the general formula (1-3). In this case, the locationswhere the phosphorescence emitting material and the compound representedby any one of the general formula (1-1) to the general formula (1-3) arecontained are not particularly limited. In the present invention, it ismore preferred that the organic layers include a light emitting layercontaining the phosphorescence emitting material and other organiclayers, and the light emitting layer contains the compound representedby any one of the general formula (1-1) to the general formula (1-3). Inthis case, it is preferred that the compound represented by any one ofthe general formula (1-1) to the general formula (1-3) is used as a hostmaterial (hereinafter, sometimes referred to as a host compound) of thelight emitting layer.

In the present invention, the compound represented by any one of thegeneral formula (1-1) to the general formula (1-3) is not limited in itsuse, and may be contained in any layer of the organic layers between thecathode and the anode of the organic electroluminescent element. Thelayer in which the compound represented by any one of the generalformula (1-1) to the general formula (1-3) is introduced is preferablythe light emitting layer, a layer between the light emitting layer andthe cathode, or a layer between the light emitting layer and the anode,and the compound may be contained in one layer or plural layers thereof.The compound is more preferably contained in any one of the lightemitting layer, a hole injecting layer, a hole transporting layer, anelectron transporting layer, an electron injecting layer, an excitonblocking layer and a charge blocking layer (a hole blocking layer, anelectron blocking layer, etc.) or in plural layers thereof, especiallypreferably contained in anyone of the light emitting layer, an excitonblocking layer, a charge blocking layer, an electron transporting layerand an electron injecting layer, and more especially preferablycontained in the light emitting layer or a hole blocking layer.

In the present invention, the compound represented by any one of thegeneral formula (1-1) to the general formula (1-3) is preferablycontained in the light emitting layer, an organic layer adjacent to thelight emitting layer between the light emitting layer and the cathode(an layer adjacent to the light emitting layer on the cathode side), andan electron injecting layer adjacent to the cathode on the lightemitting layer side, more preferably contained in any one of the lightemitting layer and a layer adjacent to the light emitting layer on thecathode side, and still more preferably contained in the light emittinglayer. Alternatively, the compound represented by any one of the generalformula (1-1) to the general formula (1-3) may be contained in bothlayers of the light emitting layer and a layer adjacent to the lightemitting layer on the cathode side.

<<Case where the Compound Represented by any One of the General Formula(1-1) to the General Formula (1-3) is Contained in the Light EmittingLayer as a Host Material of the Light Emitting Layer>>

In the case where the compound represented by any one of the generalformula (1-1) to the general formula (1-3) is contained in the lightemitting layer as a host material of the light emitting layer, thecompound represented by any one of the general formula (1-1) to thegeneral formula (1-3) is preferably contained in an amount of 0.1 to 99%by mass, more preferably 1 to 97% by mass, and still more preferably 10to 96% by mass, relative to the total mass of the light emitting layer.

In the case where the compound represented by any one of the generalformula (1-1) to the general formula (1-3) is used as a host material ofthe light emitting layer, the maximum emission wavelength (hereinafter,sometimes referred to as emission peak wavelength) of the light emittingmaterial is preferably 400 to 700 nm, more preferably 470 to 600 nm,still more preferably 490 to 550 nm, and most preferably 510 to 540 nm.

<<Case where the Compound Represented by any One of the General Formula(1-1) to the General Formula (1-3) is Contained in a Layer Other thanthe Light Emitting Layer>>

It is also preferred that the organic layers include a light emittinglayer containing the phosphorescence emitting material and other organiclayers, and the other organic layers disposed between the light emittinglayer and the cathode contain a compound having a structure representedby any one of the general formula (1-1) to the general formula (1-3).Among such cases, it is more preferred that the organic layers includean electron transporting layer or a hole blocking layer (more preferablya hole blocking layer), and the electron transporting layer or the holeblocking layer contains the compound represented by any one of thegeneral formula (1-1) to the general formula (1-3). In the case wherethe compound represented by any one of the general formula (1-1) to thegeneral formula (1-3) is contained in a layer other than the lightemitting layer, the compound is preferably contained in an amount of 70to 100% by mass, and more preferably 85 to 100% by mass, relative to thetotal mass of the layers other than the light emitting layer.

A number of layers may be provided for each of these organic layers.When providing plural layers, the layers may be formed from the samematerial or from different materials for respective layers.

(Method for Forming Organic Layer)

The organic layers in the organic electroluminescent element accordingto the present invention can be suitably formed by any of dry filmforming methods such as a deposition method and a sputtering method, andwet type film forming methods (solution coating methods) such as atransfer method, a printing method, a spin coating method, and a barcoating method.

In the organic electroluminescent element according to the presentinvention, the organic layers disposed between the pair of electrodespreferably contain at least one layer formed by vapor deposition of acomposition containing the compound represented by any one of thegeneral formula (1-1) to the general formula (1-3).

(Light Emitting Layer)

The light emitting layer is a layer having a function of, uponapplication of an electric field, receiving holes from the anode, thehole injecting layer or the hole transporting layer, receiving electronsfrom the cathode, the electron injecting layer or the electrontransporting layer, providing a recombination site of the holes and theelectrons, and thereby causing light emitting. However, the lightemitting layer in the present invention is not necessarily limited tothe light emitting by such a mechanism. The light emitting layer in theorganic electroluminescent element according to the present inventionpreferably contains at least one phosphorescence emitting material.

The light emitting layer in the organic electroluminescent elementaccording to the present invention may be configured only of the lightemitting material, or may have a configuration of the layer in which ahost material and the light emitting material are mixed. A single, ortwo or more light emitting materials may be used. The host material ispreferably a charge transporting material. A single material or two ormore materials may be used as the host material. Examples thereofinclude a configuration in which an electron transporting host materialand a hole transporting host material are mixed. Furthermore, the lightemitting layer may contain a material which does not have chargetransporting property and does not emit light.

In addition, the light emitting layer may be made of a single layer ormultiple layers including two or more layers. The layers may include thesame light emitting material or host material, or also may includedifferent materials for the respective layers. In the case where plurallight emitting layers are present, the light emitting layers may emitlight in different luminous colors from one another.

The thickness of the light emitting layer is not particularly limited,but it is usually from 2 nm to 500 nm, and above all, from the viewpointof external quantum efficiency, it is more preferably from 3 nm to 200nm, and still more preferably from 5 nm to 100 nm.

In the organic electroluminescent element according to the presentinvention, it is a preferred embodiment that the light emitting layercontains the compound represented by any one of the general formula(1-1) to the general formula (1-3), and it is a more preferredembodiment that the compound represented by any one of the generalformula (1-1) to the general formula (1-3) is used as a host material ofthe light emitting layer. Here, the host material as referred to in thepresent specification is a compound which chiefly plays a role ininjecting or transporting charges in the light emitting layer and isalso a compound which does not substantially emit light in itself. Asused herein, it is meant by the terms “which does not substantially emitlight” that the amount of light emission from the compound which doesnot substantially emit light is preferably not more than 5%, morepreferably not more than 3%, and still more preferably not more than 1%,relative to the total amount of light emission in the whole of theelement.

The light emitting material, and host materials other than the compoundrepresented by any one of the general formula (1-1) to the generalformula (1-3), as the materials for the light emitting layer, aredescribed in turn below. Incidentally, the compound represented by anyone of the general formula (1-1) to the general formula (1-3) may beused as a material other than one for the light emitting layer, in theorganic electroluminescent element according to the present invention.

(Light Emitting Material)

As the light emitting material in the present invention, any of aphosphorescence emitting material, a fluorescence emitting material, andthe like may be used.

The light emitting layer in the present invention may contain two ormore light emitting materials in order to enhance color purity or toexpand the emission wavelength range. At least one of the light emittingmaterials is preferably a phosphorescence emitting material.

In the present invention, in addition to the at least onephosphorescence emitting material contained in the light emitting layer,a fluorescence emitting material, or a phosphorescence emitting materialthat is different from the phosphorescence emitting material containedin the light emitting layer can be used as the light emitting material.

The fluorescence emitting material or the phosphorescence emittingmaterial is described in detail in, for example, paragraphs [0100] to[0164] of JP-A-2008-270736, and paragraphs [0088] to [0090] ofJP-A-2007-266458, and the matters described in these patent publicationsmay be applied to the present invention.

Examples of the phosphorescence emitting material usable in the presentinvention include, phosphorescence emitting compounds described inpatent publications such as, for example, U.S. Pat. No. 6,303,238B1,U.S. Pat. No. 6,097,147, WO 00/57676, WO 00/70655, WO 01/08230, WO01/39234A2, WO 01/41512A1, WO 02/02714A2, WO 02/15645A1, WO 02/44189A1,WO 05/19373A2, JP-A-2001-247859, JP-A-2002-302671, JP-A-2002-117978,JP-A-2003-133074, JP-A-2002-235076, JP-A-2003-123982, JP-A-2002-170684,EP 1211257, JP-A-2002-226495, JP-A-2002-234894, JP-A-2001-247859,JP-A-2001-298470, JP-A-2002-173674, JP-A-2002-203678, JP-A-2002-203679,JP-A-2004-357791, JP-A-2006-256999, JP-A-2007-19462, JP-A-2007-84635,JP-A-2007-96259, WO 07/095,118, WO 10/111,175, WO 10/027,583, WO10/028,151, etc., and among them, more preferred examples of the lightemitting material include phosphorescence emitting metal complexcompounds such as iridium (Ir) complex, platinum (Pt) complex, Cucomplex, Re complex, W complex, Rh complex, Ru complex, Pd complex, Oscomplex, Eu complex, Tb complex, Gd complex, Dy complex, Ce complex,etc. Especially preferred light emitting material is iridium (Ir)complex, platinum (Pt) complex, or Re complex, and among them, preferredare iridium (Ir) complex, platinum (Pt) complex or Re complex containingat least one coordination form from among metal-carbon bond,metal-nitrogen bond, metal-oxygen bond and metal-sulfur bond.Furthermore, in terms of luminous efficiency, driving durability,chromaticity, and the like, iridium (Ir) complex and platinum (Pt)complex are especially preferred, and iridium (Ir) complex is mostpreferred.

As the phosphorescence emitting material contained in the light emittinglayer according to the present invention, iridium (Ir) complexrepresented by the general formula (E-1) described below, or theplatinum (Pt) complex described below is preferably used.

In the general formula (E-1), Z¹ and Z² each independently represent acarbon atom or a nitrogen atom. A₁ represents an atomic group thattogether with Z¹ and a nitrogen atom forms a 5- or 6-membered heteroring. B₁ represents an atomic group that together with Z² and a carbonatom forms a 5- or 6-membered ring. Z¹ and Z² each independentlyrepresent a carbon atom or a nitrogen atom. (X—Y) represents amono-anionic bidentate ligand. n_(E1) represents an integer of 1 to 3.

Z¹ and Z² each are preferably a carbon atom. n_(E1) is preferably 2 or3, and in this case, two or three ligands each containing Z¹, Z², A₁ andB₁ exist, but the ligands may be the same as or different from oneanother.

Examples of the 5- or 6-membered hetero ring containing A₁, Z¹ and anitrogen atom include a pyridine ring, a pyrimidine ring, a pyrazinering, a triazine ring, an imidazole ring, a pyrazole ring, an oxazolering, a thiazole ring, a triazole ring, an oxadiazole ring, athiadiazole ring, etc. The 5- or 6-membered hetero ring formed of A₁, Z¹and a nitrogen atom may have a substituent.

Examples of the 5- or 6-membered ring formed of B₁, Z² and a carbon atominclude a benzene ring, a pyridine ring, a pyrimidine ring, a pyrazinering, a pyridazine ring, a triazine ring, an imidazole ring, a pyrazolering, an oxazole ring, a thiazole ring, a triazole ring, an oxadiazolering, a thiadiazole ring, a thiophene ring, a furan ring, a pyrrolering, etc. The 5- or 6-membered ring formed of B₁, Z² and a carbon atommay have a substituent.

As the substituent, the Substituent Group A is exemplified. Thesubstituents may be connected together to form a ring. Examples of thethus formed ring include an unsaturated 4- to 7-membered ring, a benzenering, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidinering, an imidazole ring, an oxazole ring, a thiazole ring, a pyrazolering, a thiophene ring, a furan ring, etc. The thus formed ring may havea substituent, and may form a further ring via a substituent on theformed ring. In addition, a substituent on the 5- or 6-membered heteroring formed of the A₁, Z¹ and a nitrogen atom and a substituent on the5- or 6-membered ring formed of the B₁, Z² and a carbon atom may beconnected together to form a fused ring similar to one described above.A further ring may be formed via a substituent on the formed ring.

Examples of the ligand represented by (X—Y) include various knownligands used in conventionally known metal complexes such as, forexample, ligands described in “Photochemistry and Photophysics ofCoordination Compounds” (written by H. Yersin, Springer-Verlag (1987)),nitrogen-containing heteroaryl ligands and diketone ligands, andpreferred are the following general formulae (1-1) to (1-39), morepreferred are the general formulae (1-1), (1-4), (1-15), (1-16), (1-17),(1-18), (1-19), (1-22), (1-25), (1-28), (1-29), (1-36) and (1-39). Thepresent invention is however not limited thereto

* represents a coordination site to the iridium (Ir) in the generalformula (E-1). Rx, Ry and Rz each independently represent a hydrogenatom or a substituent. Examples of the substituent include substituentsselected from the Substituent Group A mentioned above. Rx and Rzpreferably each independently represent an alkyl group, a perfluoroalkylgroup or an aryl group. Ry is preferably any one of a hydrogen atom, analkyl group, a perfluoroalkyl group, a fluorine atom, a cyano group andan aryl group. The plural Rxs and Rys present in one ligand may be thesame as or different from one another.

The complex having such a ligand can be synthesized in a similar mannerto a known example of the synthesis, by using a corresponding ligandprecursor.

A preferred embodiment of the iridium (Ir) complex represented by thegeneral formula (E-1) is the iridium (Ir) complex represented by thefollowing general formula (E-2).

In the general formula (E-2), A^(E1) to A^(E8) each independentlyrepresent a nitrogen atom or C—R^(E). R^(E) represents a hydrogen atomor a substituent. As the substituent, those exemplified above as theSubstituent Group A may be applied. R^(E)s may be connected to eachother to form a ring. Examples of the formed ring include those similarto the fused rings described above in the general formula (E-1). (X—Y)and n_(E2) have the same definitions as (X—Y) and n_(E1) in the generalformula (E-1), and preferred ranges thereof are also the same asdescribed above. When n_(E2) is 2 or 3, two or three ligands eachcontaining A^(E1) to A^(E8) exist, but the ligands may be the same as ordifferent from one another.

A preferred embodiment of the compound represented by the generalformula (E-2) is a compound represented by the following general formula(E-3).

In the general formula (E-3), R^(T1), R^(T2), R^(T3), R^(T4), R^(T5),R^(T6) and R^(T7) have the same definition as the above R^(E). Arepresents CR″″ or a nitrogen atom and R″″ has the same definition asthe above R^(E). Any adjacent two of R^(T1) to R^(T7) and R″″ may bebound to each other to form a fused 4- to 7-membered ring. The fused 4-to 7-membered ring is cycloalkene, cycloalkadiene, aryl or heteroaryl,and the fused 4- to 7-membered ring may further have a substituentrepresented by the Substituent Group A. (X—Y) and n_(E3) have the samedefinitions as (X—Y) and n_(E1) in the general formula (E-1), and thepreferred ranges thereof are also the same as described above. Whenn_(E3) is 2 or 3, two or three ligands each containing R^(T1), R^(T2),R^(T3), R^(T4), R^(T5), R^(T6), R^(T7) and A exist, but the ligands maybe the same as or different from one another.

Preferred ranges of A and R^(T1) to R^(T7) vary depending on theluminescent color required according to the use. The preferred range isdescribed for three different regions of the intended luminescent color:blue to light blue, green to yellow, and yellowish orange to red, butnot limited to these descriptions.

In order to obtain a yellowish orange to red luminescent color, thecompound represented by the general formula (E-1) is preferably acompound represented by the following general formula (E-4), thefollowing general formula (E-5) or the following general formula (E-6)below.

R^(T1) to R^(T4), R^(T7), A (CR″″ or a nitrogen atom), (X—Y) and n_(E4)in the general formula (E-4) have the same definitions as R^(T1) toR^(T4), R^(T7), A, (X—Y) and n_(E3) in the general formula (E-3). R₁′ toR₄′ have the same definitions as the above-described R^(E).

Any adjacent two of R^(T1) to R^(T4), R^(T7), R₁′ to R₄′ and R″″ may bebound to each other to form a fused 4- to 7-membered ring, the fused 4-to 7-membered ring is cycloalkene, cycloalkadiene, aryl or heteroaryl,and the fused 4- to 7-membered ring may further have a substituentrepresented by the Substituent Group A.

When n_(E4) is 2 or 3, two or three ligands each containing R^(T1) toR^(T4), R^(T7), A and R₁′ to R₄′ exist, but the ligands may be the sameas or different from one another.

R₁′ to R₄′ are each preferably a hydrogen atom, a fluorine atom, analkyl group or an aryl group. It is preferred that while A representsCR″″, zero to three of R^(T1) to R^(T4), R^(T7) and R″″ each representan alkyl group or a phenyl group, and all the remaining groups thereofeach are a hydrogen atom.

Specific examples of the compound represented by the general formula(E-4) are listed below, but the compound is not limited thereto.

R^(T2) to R^(T6), A (CR″″ or a nitrogen atom), (X—Y) and n_(E5) in thegeneral formula (E-5) have the same definitions as R^(T2) to R^(T6), A,(X—Y) and n_(E3) in the general formula (E-3). R₅′ to R₈′ have the samedefinitions as R₁′ to R₄′ in the general formula (E-4).

Any adjacent two of R^(T2) to R^(T6), R₅′ to R₈′, R″″ may be bound toeach other to form a fused 4- to 7-membered ring, the fused 4- to7-membered ring is cycloalkene, cycloalkadiene, aryl or heteroaryl, andthe fused 4- to 7-membered ring may further have a substituentrepresented by the Substituent Group A.

When n_(E5) is 2 or 3, two or three ligands each containing R^(T2) toR^(T6), A and R₅′ to R₈′ exist, but the ligands may be the same as ordifferent from one another.

In addition, preferred ranges of R₅′ to R₈′ are the same as thepreferred ranges of R₁′ to R₄′ in the general formula (E-4). It ispreferred that while A represents CR″″, zero to three of R^(T2) toR^(T6), R″″, and R₅′ to R₈′ are each an alkyl group or a phenyl group,and all the remaining groups are each a hydrogen atom.

Specific preferred examples of the compound represented by the generalformula (E-5) are listed below, but the compound is not limited thereto.

R^(T1) to R^(T5), A (CR″″ or a nitrogen atom), (X—Y) and n_(E6) in thegeneral formula (E-6) have the same definitions as R^(T1) to R^(T5), A,(X—Y) and n_(E3) in the general formula (E-3). R₉′ to R₁₂′ have the samedefinitions as R₁′ to R₄′ in the general formula (E-4).

Any adjacent two of R^(T1) to R^(T5), R₉′ to R₁₂′ and R″″ may be boundto each other to form a fused 4- to 7-membered ring, the fused 4- to7-membered ring is cycloalkene, cycloalkadiene, aryl or heteroaryl, andthe fused 4- to 7-membered ring may further have a substituentrepresented by the Substituent Group A.

When n_(E6) is 2 or 3, two or three ligands each containing R^(T1) toR^(T5), A and R₉′ to R₁₂′ exist, but the ligands may be the same as ordifferent from one another.

Preferred ranges of R₉′ to R₁₂′ are the same as the preferred ranges ofR₁′ to R₄′ in the general formula (E-4). It is preferred that while Arepresents CR″″, zero to three of R^(T1) to R^(T5), R″″, and R₉′ to R₁₂′each represent an alkyl group or a phenyl group, and all the remaininggroups thereof are each a hydrogen atom.

Specific preferred examples of the compound represented by the generalformula (E-6) are listed below, but the compound is not limited thereto.

In order to obtain a green to yellow luminescent color, the compoundrepresented by the general formula (E-1) described above is preferably acompound represented by the following general formula (E-7).

In the general formula (E-7), R^(T1), R^(T2), R^(T3), R^(T4), R^(T5),R^(T6), R^(T7), R″″, (X—Y) and n_(E3) have the same definitions asR^(T1), R^(T2), R^(T3), R^(T4), R^(T5), R^(T6), R^(T7), R″″, (X—Y) andn_(E3) in the general formula (E-3). Any adjacent two of R^(T1) toR^(T7), and R″″ may be bound to each other to form a fused 4- to7-membered ring, the fused 4- to 7-membered ring is cycloalkene,cycloalkadiene, aryl or heteroaryl, and the fused 4- to 7-membered ringmay further have a substituent represented by the Substituent Group A.

When n_(E7) is 2 or 3, two or three ligands containing R^(T1), R^(T2),R^(T3), R^(T4), R^(T5), R^(T6), R^(T7) and R″″ exist, but the ligandsmay be the same as or different from one another.

R^(T1), R^(T2), R_(T3), R^(T4), R^(T5), R^(T6), R^(T7) and R″″ each arepreferably a hydrogen atom, a fluorine atom, an alkyl group, an arylgroup, a heteroaryl group or a cyano group.

n_(E7) is preferably 3, and the general formula (E-7) is furtherpreferably a compound represented by the general formula (E-7-1).

In the general formula (E-7-1), R^(T1), R^(T2), R^(T3), R^(T4), R^(T5),R^(T6), R^(T7) and R″″ have the same definitions as R^(T1), R^(T2),R^(T3), R^(T4), R^(T5), R^(T6), R^(T7) and R″″ in the general formula(E-7), and the preferred ranges thereof are also the same. R^(T8) toR^(T15) have the same definitions as R^(T1), R^(T2), R^(T3), R^(T4),R^(T5), R^(T6), R^(T7), R″″, and the preferred ranges thereof are alsothe same. However, the phenylpyridine ligand containing R^(T1), R^(T2),R^(T3), R^(T4), R^(T5), R^(T6), R^(T7) and R″″ and the phenylpyridineligand containing R^(T8) to R^(T15) are different from each other.

In order to obtain a luminescent color closer to green among the greento yellow luminescent colors, it is preferred that R^(T1), R^(T2),R^(T3), R^(T4), R^(T5), R^(T6), R^(T7) and R″″ each are a hydrogen atom,a fluorine atom, an alkyl group or a cyano group, and it is morepreferred that one to three of the R^(T1), R^(T5), R^(T4) and R″″ eachare an alkyl group. R^(T8) to R^(T11) each are preferably a hydrogenatom or an alkyl group. R^(T12) to R^(T15) each are preferably ahydrogen atom, an alkyl group, a cyano group or an aryl group. Thesubstituted position by the alkyl group, the cyano group or the arylgroup is preferably on R^(T13) or R^(T14). The aryl group may furtherhave a substituent, or may form a fused ring via a substituent.

In order to obtain a luminescent color closer to yellow among the greento yellow luminescent colors, it is preferred that R^(T1), R^(T2),R^(T3), R^(T4), R^(T5), R^(T6), R^(T7) and R″″ each are a hydrogen atomand an alkyl group, and it is more preferred that one to three of theR^(T1), R^(T5), R^(T4), R″″ each are an alkyl group. It is preferredthat at least one of R^(T8) to R^(T11) is an aryl group, and it is morepreferred that either one of R^(T9) and R^(T10) is an aryl group and theremaining one is a hydrogen atom or an alkyl group. The aryl group mayfurther have a substituent or may form a fused ring via a substituent.

The general formula (E-7-1) may also preferably include a partialstructure represented by the general formula (E-7-2) in the generalformula (E-7-1). When having the general formula (E-7-2), the effectssuch as decrease of voltage and enhancement of durability are sometimesexhibited significantly.

In the general formula (E-7-2), X is —O—, —S—, —NR^(T24)—,—CR^(T25)R^(T26)— or —SiR^(T27)R^(T28)—, and any one of R^(T16) toR^(T28) is bound to a part of the general formula (E-7-1) via a singlebond or via a substituent.

In the general formula (E-7-2), any one of R^(T16) to R^(T28) ispreferably bound to a part of the general formula (E-7-1) via a singlebond or via an aryl group. In the case where a luminescent color closerto green is desired, the bond to apart of the general formula (E-7-1) ismade preferably on R^(T13) or R^(T14) and more preferably on R^(T13). Inthe case where a luminescent color closer to yellow is desired, the bondis made preferably on R^(T9) or R^(T10).

X is preferably —O—, —S—, —NR^(T24)— or —CR^(T25)R^(T26)—, and morepreferably —O— or —S—.

When X is —O— or —S—, X is preferably bound to a part of the generalformula (E-7-1) via a single bond at the position of R^(T16), and when Xis —NR^(T24)—, X is preferably bound to a part of the general formula(E-7-1) via a single bond at the position of R^(T18) or R^(T24), andwhen X is —CR^(T25)R^(T26)—, X is preferably bound to a part of thegeneral formula (E-7-1) via a single bond at the position of R^(T17).

Specific preferred examples of the compound represented by the generalformula (E-7) are listed below, but the compound is not limited thereto.

In order to obtain a blue to light blue luminescent color, the compoundrepresented by the general formula (E-1) is preferably a compoundrepresented by the following general formula (E-8) or the followinggeneral formula (E-9).

R^(T1), R^(T2), R^(T3), R^(T4), R^(T5), R^(T6), R^(T7), A (CR″″ or anitrogen atom), (X—Y) and n_(E8) in the general formula (E-8) have thesame definitions as R^(T1), R^(T2), R^(T3), R^(T4), R^(T5), R^(T6),R^(T7), A, (X—Y), n_(E3) in the general formula (E-3).

R^(T1), R^(T5) to R^(T7) in the general formula (E-8) each are morepreferably a hydrogen atom, an alkyl group or an aryl group. R^(T2) toR^(T4) each are preferably a hydrogen atom, a fluorine atom or a cyanogroup. A is preferably a CR″″ wherein R″″ is a fluorine atom or a cyanogroup, or a nitrogen atom. n_(E8) is preferably 2 or 3. (X—Y) has thesame definition as (X—Y) in the general formula (E-1), and the preferredrange thereof is also the same.

Specific preferred examples of the compound represented by the generalformula (E-8) are listed below, but the compound is not limited thereto.

In the general formula (E-9), R^(T29) to R^(T34), (X—Y) and n_(E8−) havethe same definitions as R^(T1) to R^(T6), (X—Y) and n_(E3) in thegeneral formula (E-3). R^(T35) represents a substituent, and as thesubstituent, the above-mentioned Substituent Group B is exemplified. Anyadjacent two of R^(T29) to R^(T35) may be bound to each other to form afused 4- or 7-membered ring, the fused 4- or 7-membered ring iscycloalkene, cycloalkadiene, aryl or heteroaryl, and the fused 4- or7-membered ring may further have a substituent represented by theSubstituent Group A.

When n_(E7) is 2 or 3, two or three ligands each containing R^(T1),R^(T2), R^(T3), R^(T4), R^(T5), R^(T6), R^(T7) and R″″ exist, but theligands may be the same as or different from one another.

R^(T29) to R^(T34) each are preferably a hydrogen atom, an alkyl group,an aryl group or a cyano group. R^(T35) is preferably an alkyl group oran aryl group. R^(T35) is preferably connected to R^(T29) to form aring. R^(T35) and R^(T29) are preferably bound together via an arylgroup to result in forming a nitrogen-containing 6-membered ring. Thearyl group connected to R^(T35) and R^(T29) may further have asubstituent, and from the viewpoint of durability, the aryl group ispreferably substituted with an alkyl group.

Specific preferred examples of the compound represented by the generalformula (E-9) are listed below, but the compound is not limited thereto.

Specific preferred examples of the compound represented by the generalformula (E-1) other than those shown above are listed below, but thecompound is not limited thereto.

The above compound exemplified as the compound represented by thegeneral formula (E-1) can be synthesized by various methods described inJP-A-2009-99783, U.S. Pat. No. 7,279,232, and the like. It is preferredthat after the synthesis, the compound is purified by columnchromatography, recrystallization, or the like, and thereafter purifiedby sublimation purification. By sublimation purification, it is possiblenot only to separate organic impurities but also to effectively removethe inorganic salts, remaining solvent, or the like.

Although the compound represented by the general formula (E-1) ispreferably contained in the light emitting layer, the use thereof is notlimited, and the compound may also be contained in any further layer ofthe organic layers.

The compound represented by the general formula (E-1) in the lightemitting layer is contained in the light emitting layer generally in anamount of from 0.1% by mass to 50% by mass relative to the total mass ofthe compounds forming the light emitting layer, and from the viewpointof durability and external quantum efficiency, the compound ispreferably contained in an amount of from 0.2% by mass to 50% by mass,more preferably 0.3% by mass to 40% by mass, still more preferably from0.4% by mass to 30% by mass, and especially preferably from 0.5% by massto 20% by mass.

It is especially preferred in the present invention that the compoundrepresented by any one of the general formulae (1-1) to (1-3) and thecompound represented by any one of the general formulae (E-1) to (E-9)are used in combination in the light emitting layer.

Specific examples of the platinum (Pt) complex include a compounddescribed in [0143] to [0152], [0157] to [0158], and to [0168] ofJP-A-2005-310733, a compound described in to [0083] of JP-A-2006-256999,a compound described in to [0090] of JP-A-2006-93542, a compounddescribed in to [0071] of JP-A-2007-73891, a compound described in to[0083] of JP-A-2007-324309, a compound described in to [0090] ofJP-A-2006-93542, a compound described in to [0071] of JP-A-2007-96255and a compound described in [0043] to [0046] of JP-A-2006-313796.

The thickness of the light emitting layer is not particularly limited,but it is usually from 2 nm to 500 nm, and above all, from the viewpointof external quantum efficiency, it is more preferably from 5 nm to 200nm, and still more preferably from 10 nm to 100 nm.

The light emitting layer in the organic electroluminescent elementaccording to the present invention may be configured only of the lightemitting material, or may have a configuration of the layer in which ahost material and the light emitting material are mixed. A single, ortwo or more light emitting materials may be used. The host material ispreferably a charge transporting material. A single material or two ormore materials may be used as the host material. Examples thereofinclude a configuration in which an electron transporting host materialand a hole transporting host material are mixed. Furthermore, the lightemitting layer may contain a material which does not have chargetransporting property and does not emit light.

In addition, the light emitting layer may be made of a single layer ormultiple layers including two or more layers. The layers may all includethe same light emitting material or host material, or also may includedifferent materials for the respective layers. In the case where plurallight emitting layers are present, the light emitting layers may emitlight in different luminous colors from one another.

(Host Material)

The host material is a compound which chiefly plays a role in injectingor transporting charges in the light emitting layer and is also acompound which does not substantially emit light in itself. As usedherein, it is meant by the terms “which does not substantially emitlight” that the amount of light emission from the compound which doesnot substantially emit light is preferably not more than 5%, morepreferably not more than 3%, and still more preferably not more than 1%,relative to the total amount of light emission in the whole of theelement.

As the host material, the compound represented by any one of the generalformula (1-1) to the general formula (1-3) can be used.

Other examples of the host material which can be used in the organicelectroluminescent element according to the present invention includethe following compounds:

pyrrole, indole, carbazole, azaindole, azacarbazole, triazole, oxazole,oxadiazole, pyrazole, imidazole, thiophene, benzothiophene,dibenzothiophene, furan, benzofuran, dibenzofuran, polyarylalkane,pyrazoline, pyrazolone, phenylenediamine, arylamine, amino-substitutedchalcone, styrylanthracene, fluorenone, hydrazone, stilbene, silazane,an aromatic tertiary amine compound, a styrylamine compound, aporphyrin-based compound, a fused aromatic hydrocarbon compound (such asfluorene, naphthalene, phenanthrene and triphenylene), apolysilane-based compound, a poly(N-vinylcarbazole), an aniline-basedcopolymer, a thiophene oligomer, a polythiophene and other conductivehigh molecular oligomers, organic silane, carbon film, pyridine,pyrimidine, triazine, imidazole, pyrazole, triazole, oxazole,oxadiazole, fluorenone, anthraquinodimethane, anthrone, diphenylquinone,thiopyran dioxide, carbodiimide, fluorenylidenemethane,distyrylpyrazine, a fluorine-substituted aromatic compound, heterocyclictetracarboxylic anhydride of naphthalene, perylene or the like,phthalocyanine, various metal complexes typified by a metal complex ofan 8-quinolinol derivative, metal phthalocyanine and a metal complexhaving a benzoxazole or benzothiazole as a ligand, derivatives thereof(which may have a substituent or a fused ring), and the like.

Among them, carbazole, dibenzothiophene, dibenzofuran, arylamine, afused aromatic hydrocarbon compound and a metal complex are especiallypreferred.

In the light emitting layer in the organic electroluminescent elementaccording to the present invention, the host material which can be usedtogether may be a hole transporting host material or an electrontransporting host material.

In the light emitting layer, it is preferred that the triplet minimumexcited energy (T₁ energy) in the film state of the host material ishigher than T₁ energy of the phosphorescence emitting material in termsof the color purity, luminous efficiency, and driving durability. The T₁of the host material is preferably higher than the T₁ of thephosphorescence emitting material by 0.1 eV or more, more preferably by0.2 eV or more, and still more preferably by 0.3 eV or more.

Since the light emission is quenched when T₁ of the host material in thefilm state is lower than T₁ of the phosphorescence emitting material,the host material is required to have a higher T₁ than thephosphorescence emitting material. Even in the case where the hostmaterial has a higher T₁ than the phosphorescence emitting material,when the difference between both T₁s is small, reverse energy transferfrom the phosphorescence emitting material to the host materialpartially occurs to cause a deterioration in efficiency and durability.Accordingly, a host material is demanded that has a sufficiently high T₁and has favorable chemical stability and carrier injecting andtransporting properties.

Content of the host compound in the light emitting layer in the organicelectroluminescent element according to the present invention is notparticularly limited, but is preferably 15% by mass to 95% by massrelative to the total mass of the compounds constituting the lightemitting layer, from the viewpoint of the luminous efficiency and thedriving voltage. When the light emitting layer contains plural hostcompounds containing the compound represented by any one of the generalformula (1-1) to the general formula (1-3), the compound represented byany one of the general formula (1-1) to the general formula (1-3)preferably accounts for 50% by mass to 99% by mass of the total hostcompounds.

(Other Layers)

The organic electroluminescent element according to the presentinvention may include layers other than the light emitting layer.

Examples of the organic layer other than the light emitting layer whichmay be included in the organic layers include a hole injecting layer, ahole transporting layer, a blocking layer (e.g., a hole blocking layer,an exciton blocking layer, and the like), and an electron transportinglayer. Specifically, examples of the layer configuration include thosedescribed below, but it should not be construed that the presentinvention is limited to these configurations.

Anode/hole transporting layer/light emitting layer/electron transportinglayer/cathode

Anode/hole transporting layer/light emitting layer/blockinglayer/electron transporting layer/cathode

Anode/hole transporting layer/light emitting layer/blockinglayer/electron transporting layer/electron injecting layer/cathode

Anode/hole injecting layer/hole transporting layer/light emittinglayer/blocking layer/electron transporting layer/cathode

Anode/hole injecting layer/hole transporting layer/light emittinglayer/electron transporting layer/electron injecting layer/cathode

Anode/hole injecting layer/hole transporting layer/light emittinglayer/blocking layer/electron transporting layer/electron injectinglayer/cathode

Anode/hole injecting layer/hole transporting layer/blocking layer/lightemitting layer/blocking layer/electron transporting layer/electroninjecting layer/cathode

The organic electroluminescent element according to the presentinvention preferably includes at least one (A) organic layer which ispreferably disposed between the anode and the light emitting layer.Examples of the (A) organic layer which is preferably disposed betweenthe anode and the light emitting layer include an hole injecting layer,a hole transporting layer, and an electron blocking layer from the anodeside.

The organic electroluminescent element according to the presentinvention preferably includes at least one (B) organic layer which ispreferably disposed between the cathode and the light emitting layer.Examples of the (B) organic layer which is preferably disposed betweenthe cathode and the light emitting layer include an electron injectinglayer, an electron transporting layer, and a hole blocking layer fromthe cathode side.

Specifically, an example of the preferred embodiments of the organicelectroluminescent element according to the present invention is theembodiment shown in FIG. 1, in which a hole injecting layer 4, a holetransporting layer 5, a light emitting layer 6, a hole blocking layer 7,and an electron transporting layer 8 are laminated as the organiclayers, in this order from the anode 3 side.

These layers other than the light emitting layer which the organicelectroluminescent element according to the present invention may haveare hereunder described.

(A) Organic Layer Preferably Disposed Between Anode and Light EmittingLayer:

First, the (A) organic layer preferably disposed between the anode andthe light emitting layer is described.

(A-1) Hole Injecting Layer and Hole Transporting Layer:

The hole injecting layer and the hole transporting layer are layershaving a function of receiving holes from the anode or the anode sideand transporting them to the cathode side.

For the hole injecting layer and the hole transporting layer, thematters described in paragraphs [0165] to [0167] of JP-A-2008-270736 canbe applied to the present invention. Among them, materials which arepreferably used as a hole injecting layer or a hole transporting layerare described.

The organic electroluminescent element according to the presentinvention preferably contains the following compound in organic layersbetween the light emitting layer and the anode, and more preferably in ahole injecting layer.

Specifically, a compound having the following structure is preferred.

The organic electroluminescent element according to the presentinvention preferably contains at least one compound represented by anyone of the following general formula (HT-1) and the general formula(1-1) to the general formula (1-3) in an organic layer between the lightemitting layer and the anode, more preferably in a hole transportinglayer or an electron blocking layer.

Examples of the hole transporting material include a triarylaminecompound represented by the following general formula (HT-1):

[wherein in the general formula (HT-1), R^(A1) to R^(A15) represent ahydrogen atom or a substituent].

Examples of the substituent represented by R^(A1) to R^(A15) includesubstituents exemplified in the Substituent Group A, and adjacentsubstituents may be bound together via a single bond or a linking groupto form a ring. From the viewpoint of the heat resistance anddurability, at least one of R^(A1) to R^(A5) and at least one of R^(A6)to R^(A10) are each an aryl group.

Specific examples of the general formula (HT-1) are shown below, but thepresent invention is not limited thereto.

When the compound represented by the general formula (HT-1) is used in ahole transporting layer, the compound represented by the general formula(HT-1) is preferably contained in an amount of 50 to 100% by mass, morepreferably 80 to 100% by mass, and especially preferably 95 to 100% bymass.

When the compound represented by the general formula (HT-1) is used inplural organic layers, the compound is preferably contained in an amountwithin the above range in each layer.

A single compound represented by the general formula (HT-1) may becontained in any organic layer, or plural compounds represented by thegeneral formula (HT-1) may be contained in combination in an arbitraryratio.

The thickness of the hole transporting layer containing the compoundrepresented by the general formula (HT-1) is preferably 1 nm to 500 nm,more preferably 3 nm to 200 nm, and still more preferably 5 nm to 100nm. In addition, the hole transporting layer is preferably provided incontact with the light emitting layer.

The hole transporting layer may have either a single layer structurecomposed of a single material or two or more materials selected from theabove-exemplified materials, or a multilayer structure composed of aplurality of layers having the same composition or differentcompositions.

The compound represented by the general formula (HT-1) preferably has aminimum excited triplet (T₁) energy in the film state of 2.52 eV (58kcal/mol) to 3.47 eV (80 kcal/mol), more preferably of eV (57 kcal/mol)to 3.25 eV (75 kcal/mol), and still more preferably of 2.52 eV (58kcal/mol) to 3.04 eV (70 kcal/mol).

The hydrogen atoms constituting the general formula (HT-1) may includehydrogen isotopes (deuterium or the like). In this case, all thehydrogen atoms in the compound may be replaced by the hydrogen isotopeatoms, or the compound may be a mixture in which apart of the compoundcontains some hydrogen isotopes.

The compound represented by the general formula (HT-1) can besynthesized by combining various known synthesis methods. Most commonly,for the carbazole compound, a synthetic method may be exemplified inwhich a fused compound of an arylhydradine and a cyclohexane derivativeis subjected to the Aza-Cope rearrangement reaction, and thereafterconverted into an aromatic compound by dehydrogenating (written by L. F.Tieze and Th. Eicher, translated by Takano and Ogasawara, Seimitsu YuukiGousei, p 339 (Nankodo)). For a coupling reaction of the resultingcarbazole compound with a halogenated aryl compound using a palladiumcatalyst, a method is exemplified which is described in TetrahedronLetters, vol. 39, p 617 (1998); vol. 39, p 2367 (1998); vol. 40, p 6393(1999); etc. The reaction temperature and the reaction time are notparticularly limited and the conditions described in the above documentsmay be applied.

The compound represented by the general formula (HT-1) in the presentinvention is preferably formed into a thin film by a vacuum vapordeposition process, but a wet process such as a solution coating can besuitably used. The molecular weight of the compound is preferably 2000or less, more preferably 1200 or less, and especially preferably 800 orless, from the viewpoint of applicability to the vapor deposition andsolubility. In terms of the applicability to the vapor deposition, toosmall molecular weight causes decrease of the vapor pressure, therebyinhibiting the conversion from the vapor phase to the solid phase, sothat it become difficult to form the organic layer. Accordingly, themolecular weight is preferably 250 or more, and especially preferably300 or more.

(A-2) Electron Blocking Layer:

The electron blocking layer is a layer having a function of preventingthe electrons, which have been transported from the cathode side to thelight emitting layer, from passing through to the anode side. In thepresent invention, the electron blocking layer can be provided as anorganic layer adjacent to the light emitting layer on the anode side.

As the organic compound constituting the electron blocking layer, forexample, those exemplified above as the hole transporting material canbe used.

The thickness of the electron blocking layer is preferably from 1 nm to500 nm, more preferably from 3 nm to 100 nm, and still more preferablyfrom 5 nm to 50 nm.

The electron blocking layer may have either a single layer structurecomposed of a single material or two or more materials selected from theabove-exemplified materials or a multilayer structure composed of aplurality of layers having the same composition or differentcompositions.

The material used for the electron blocking layer preferably has a T₁energy higher than that of the phosphorescence emitting material interms of the color purity, luminous efficiency and driving durability.The T₁ in the film state of the material used for the electron blockinglayer is preferably higher than the T₁ of the phosphorescence emittingmaterial by 0.1 eV or more, more preferably by 0.2 eV or more, and stillmore preferably by 0.3 eV or more.

(B) Organic Layer Preferably Disposed Between Cathode and Light EmittingLayer:

Next, the (B) organic layer preferably disposed between the cathode andthe light emitting layer is described.

(B-1) Electron Injecting Layer and Electron Transporting Layer:

The electron injecting layer and the electron transporting layer arelayers having a function of receiving electrons from the cathode or thecathode side and transporting them to the anode side. The electroninjecting material and the electron transporting material used in theselayers may be either a low-molecular compound or a high-molecularcompound.

As the electron transporting material, for example, the compoundrepresented by any one of the general formula (1-1) to the generalformula (1-3) can be used. A preferred embodiment of this case is thesame as the above description of the case where the compound representedby any one of the general formula (1-1) to the general formula (1-3) iscontained in a layer other than the light emitting layer. These layersalso preferably contain, as an other electron transporting material,pyridine derivatives, quinoline derivatives, pyrimidine derivatives,pyrazine derivatives, phthalazine derivatives, phenanthrolinederivatives, triazine derivatives, triazole derivatives, oxazolederivatives, oxadiazole derivatives, imidazole derivatives, fluorenonederivatives, anthraquinodimethane derivatives, anthrone derivatives,diphenylquinone derivatives, thiopyranedioxide derivatives, carbodiimidederivatives, fluorenylidenemethane derivatives, distyrylpyrazinederivatives, aromatic ring tetracarboxylic acid anhydrides ofnaphthalene, perylene and the like, phthalocyanine derivatives, variousmetal complexes typified by metal complexes of 8-quinolinol derivatives,metal phthalocyanine and metal complexes having benzoxazole orbenzothiazole as a ligand thereof, organic silane derivatives typifiedby silole, and the like.

From the viewpoint of decreasing the driving voltage, the thickness ofeach of the electron injecting layer and the electron transporting layeris preferably not more than 500 nm.

The thickness of the electron transporting layer is preferably from 1 nmto 500 nm, more preferably from 5 nm to 200 nm, and still morepreferably from 10 nm to 100 nm. The thickness of the electron injectinglayer is preferably from 0.1 nm to 200 nm, more preferably from 0.2 nmto 100 nm, and still more preferably from 0.5 nm to 50 nm.

The electron injecting layer and the electron transporting layer mayhave either a single layer structure composed of a single material ortwo or more materials selected from the above-exemplified materials or amultilayer structure composed of a plurality of layers having the samecomposition or different compositions.

The electron injecting layer preferably contains an electron donatingdopant. By incorporating the electron donating dopant into the electroninjecting layer, for example, there are brought such effects that theelectron injecting properties are enhanced; that the driving voltage islowered; and that the efficiency is enhanced. The electron donatingdopant may be any one of organic materials and inorganic materials aslong as it is capable of giving electrons to the material to be dopedand generating radical anions. Examples thereof include dihydroimidazolecompounds such as tetrathiafulvalene (TTF), tetrathianaphthacene (TTT),and bis-[1,3-diethyl-2-methyl-1,2-dihydrobenzimidazolyl], lithium, andcesium.

The electron donating dopant in the electron injecting layer iscontained in the amount of preferably from 0.01% by mass to 50% by mass,more preferably from 0.1% by mass to 40% by mass, and still morepreferably from 0.5% by mass to 30% by mass relative to the total massof the compounds forming the electron injecting layer.

(B-2) Hole Blocking Layer:

The hole blocking layer is a layer having a function of preventingholes, which have been transported from the anode side to the lightemitting layer, from passing through to the cathode side. In the presentinvention, the hole blocking layer can be provided as an organic layeradjacent to the light emitting layer on the cathode side.

In order to inhibit the energy transfer of excitons generated in thelight emitting layer to prevent degradation of luminous efficiency, T₁energy in the film state of the organic compound constituting the holeblocking layer is preferably higher than the T₁ energy of the lightemitting material.

As an example of the organic compound constituting the hole blockinglayer, for example, the compound represented by any one of the generalformula (1-1) to the general formula (1-3) can be used.

Examples of the organic compounds constituting the hole blocking layer,other than the compound represented by any one of the general formula(1-1) to the general formula (1-3), include aluminum complexes such asaluminum(III) bis(2-methyl-8-quinolinato) 4-phenylphenolate (abbreviatedas “Balq”), triazole derivatives, phenanthroline derivatives such as2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (abbreviated as “BCP”),the compound of the present invention, and the like. In the presentinvention, the function of the hole blocking layer is not limited to thefunction of actually blocking the holes, and the hole blocking layer mayhave a function to prevent the excitons in the light emitting layer fromdiffusing to the electron transporting layer, or a function to blockquenching due to energy transfer. The compound of the present inventionis preferably applied to the hole blocking layer.

The thickness of the hole blocking layer is preferably from 1 nm to 500nm, more preferably from 5 nm to 200 nm, and still more preferably from10 nm to 100 nm.

The hole blocking layer may have either a single layer structurecomposed of a single material or two or more materials selected from theabove-exemplified materials or a multilayer structure composed of aplurality of layers having the same composition or differentcompositions.

The material which is used in the hole blocking layer preferably has ahigher T₁ energy than that of the phosphorescence emitting material inview of the color purity, luminous efficiency, and driving durability.The T₁ energy in the film state of the material used for the holeblocking layer is preferably higher than the T₁ of the phosphorescenceemitting material by 0.1 eV or more, more preferably by 0.2 eV or more,and still more preferably by 0.3 eV or more.

(B-3) Material Especially Preferably Used in Organic Layer which isPreferably Disposed Between Cathode and Light Emitting Layer:

In the organic electroluminescent element according to the presentinvention, examples of the material which is especially preferably usedin the materials for the (B) organic layer preferably disposed betweenthe cathode and the light emitting layer include the compoundrepresented by any one of the general formula (1-1) to the generalformula (1-3), and a compound represented by the following generalformula (O-1).

The compound represented by the general formula (O-1) is hereunderdescribed.

The organic electroluminescent element according to the presentinvention preferably contains at least one organic layer between thelight emitting layer and the cathode, and it is preferred that theorganic layer contains at least one compound represented by thefollowing general formula (O-1) from the view point of the elementefficiency and driving voltage. The general formula (O-1) is hereunderdescribed.

(In the general formula (O-1), R^(O1) represents an alkyl group, an arylgroup, or a heteroaryl group. A^(O1) to A^(O4) each independentlyrepresent C—R^(A) or a nitrogen atom. R^(A) represents a hydrogen atom,an alkyl group, an aryl group or a heteroaryl group, and plural R^(A)smay be the same as or different from one another. L^(O1) represents adivalent to hexavalent linking group composed of an aryl ring or aheteroaryl ring. n^(O1) represents an integer of from 2 to 6.)

R^(O1) represents an alkyl group (preferably having from 1 to 8 carbonatoms), an aryl group (preferably having from 6 to 30 carbon atoms), ora heteroaryl group (preferably having from 4 to 12 carbon atoms), whichmay have a substituent selected from the above-described SubstituentGroup A. R^(O1) is preferably an aryl group or a heteroaryl group, andmore preferably an aryl group. Preferred examples of the substituent inthe case where the aryl group of R^(O1) has a substituent include analkyl group, an aryl group, and a cyano group. Among them, an alkylgroup or an aryl group is more preferred, with an aryl group being stillmore preferred. In the case where the aryl group of R^(O1) has pluralsubstituents, the plural substituents may be bound to each other to forma 5- or 6-membered ring. The aryl group of R^(O1) is preferably a phenylgroup which may have a substituent selected from the Substituent GroupA, more preferably a phenyl group which may be substituted with an alkylgroup or an aryl group, and still more preferably an unsubstitutedphenyl group or a 2-phenylphenyl group.

A^(O1) to A^(O4) each independently represent C—R^(A) or a nitrogenatom. It is preferred that from zero to two of A^(O1) to A^(O4) arenitrogen atoms; and it is more preferred that zero or one of A^(O1) toA^(O4) is a nitrogen atom. It is preferred that all of A^(O1) to A^(O4)are C—Rs^(A), or A^(O1) is a nitrogen atom, and A^(O2) to A^(O4) areC—Rs^(A); it is more preferred that A^(O1) is a nitrogen atom, andA^(O2) to A^(O4) are C—Rs^(A); and it is still more preferred thatA^(O1) is a nitrogen atom, A^(O2) to A^(O4) are C—Rs^(A), and R^(A)s areall hydrogen atoms.

R^(A) represents a hydrogen atom, an alkyl group (preferably having from1 to 8 carbon atoms), an aryl group (preferably having from 6 to 30carbon atoms), or a heteroaryl group (preferably having from 4 to 12carbon atoms), and may have a substituent selected from theabove-described Substituent Group A. In addition, plural R^(A)s may bethe same as or different from one another. R^(A) is preferably ahydrogen atom or an alkyl group, and more preferably a hydrogen atom.

L^(O1) represents a divalent to hexavalent linking group composed of anaryl ring (preferably having from 6 to 30 carbon atoms) or a heteroarylring (preferably having from 4 to 12 carbon atoms). L^(O1) is preferablyan arylene group, a heteroarylene group, an aryltriyl group, or aheteroaryltriyl group, more preferably a phenylene group, a biphenylenegroup, or a benzenetriyl group, and still more preferably a biphenylenegroup or a benzenetriyl group. L^(O1) may have a substituent selectedfrom the above-described Substituent Group A, and in the case whereL^(O1) has a substituent, the substituent is preferably an alkyl group,an aryl group, or a cyano group. Specific examples of L^(O1) include thefollowing.

n^(O1) represents an integer of from 2 to 6, preferably an integer offrom 2 to 4, and more preferably 2 or 3. n^(O1) is most preferably 3from the viewpoint of efficiency of the element, and n^(O1) is mostpreferably 2 from the viewpoint of durability of the element.

The compound represented by the general formula (O-1) is preferably acompound represented by the following general formula (O-2):

(wherein in the general formula (O-2), R^(O1) represents an alkyl group,an aryl group or a heteroaryl group. R^(O2) to R^(O4) each independentlyrepresent a hydrogen atom, an alkyl group, an aryl group or a heteroarylgroup. A^(O1) to A^(O4) each independently represent C—R^(A) or anitrogen atom. R^(A) represents a hydrogen atom, an alkyl group, an arylgroup or a heteroaryl group, and the plural R^(A)s may be the same as ordifferent from one another).

R^(O1) and A^(O1) to A^(O4) have the same definitions as R^(O1) andA^(O1) to A^(O4) in the general formula (O-1) described above, and thepreferred ranges thereof are also the same.

R^(O2) to R^(O4) each independently represent a hydrogen atom, an alkylgroup (preferably having 1 to 8 carbon atoms), an aryl group (preferablyhaving 6 to 30 carbon atoms), or a heteroaryl group (preferably having 4to 12 carbon atoms), and these groups may have a substituent selectedfrom the Substituent Group A described above. R^(O2) to R^(O4) arepreferably a hydrogen atom, an alkyl group or an aryl group, morepreferably a hydrogen atom or an aryl group, and most preferably ahydrogen atom.

The glass transition temperature (Tg) of the compound represented by thegeneral formula (O-1) is preferably from 100° C. to 300° C., morepreferably from 120° C. to 300° C., still more preferably from 120° C.to 300° C., and further still more preferably 140° C. to 300° C., fromthe viewpoint of stability at the time of storage at a high temperature,or stable operation during driving at a high temperature or against heatgeneration during driving.

Specific examples of the compound represented by the general formula(O-1) are hereunder described, but the compound used in the presentinvention is not limited thereto.

The compound represented by the general formula (O-1) can be synthesizedby the method described in JP-A-2001-335776. After the synthesis, it ispreferred that the product is purified by column chromatography,recrystallization, reprecipitation, or the like, and then purified bysublimation purification. By sublimation purification, it is possiblenot only to separate organic impurities but also to effectively removeinorganic salts, remaining solvent, moisture, or the like.

In the organic electroluminescent element according to the presentinvention, the compound represented by the general formula (O-1) ispreferably contained in an organic layer between the light emittinglayer and the cathode, and more preferably contained in a layer adjacentto the light emitting layer on the cathode side.

The compound represented by the general formula (O-1) is preferablycontained in an amount of 70 to 100% by mass, and more preferably 85 to100% by mass, relative to the total mass of the organic layer to whichthe compound is to be added.

<Protective Layer>

In the present invention, the entirety of the organic electroluminescentelement may be protected by a protective layer.

For the protective layer, the detailed description in paragraphs [0169]to [0170] of JP-A-2008-270736 can be applied to the present invention.Incidentally, the materials for the protective layer may be either aninorganic material or an organic material.

<Sealing Enclosure>

For the organic electroluminescent element according to the presentinvention, the entirety of the element may be sealed using a sealingenclosure.

For the sealing enclosure, the detailed description in paragraph [0171]of JP-A-2008-270736 can be applied to the present invention.

<Driving Method>

The organic electroluminescent element according to the presentinvention can emit light by applying a direct current (it may include analternate current component, if desired) voltage (usually from 2 voltsto 15 volts) or a direct current between the anode and the cathode.

For a driving method of the organic electroluminescent element accordingto the present invention, driving methods described in the descriptionsor the like of JP-A-2-148687, JP-A-6-301355, JP-A-5-29080,JP-A-7-134558, JP-A-8-234685, and JP-A-8-241047, Japanese Patent No.2784615, and U.S. Pat. Nos. 5,828,429 and 6,023,308 can be applied.

The external quantum efficiency of the organic electroluminescentelement according to the present invention is preferably 7% or more,more preferably 10% or more, and still more preferably 12% or more. Asfor the numerical value of the external quantum efficiency, a maximumvalue of the external quantum efficiency obtained when the organicelectroluminescent element is driven at 20° C., or a value of theexternal quantum efficiency in the vicinity of from 300 to 400 cd/m²obtained when the element is driven at 20° C. can be employed.

The internal quantum efficiency of the organic electroluminescentelement according to the present invention is preferably 30% or more,more preferably 50% or more, and still more preferably 70% or more. Theinternal quantum efficiency of the element is calculated by dividing theexternal quantum efficiency by the light extraction efficiency. Thoughthe light extraction efficiency in usual organic EL elements is about20%, by adjusting the shape of a substrate, the shape of an electrode,the film thickness of an organic layer, the film thickness of aninorganic layer, the refractive index of an organic layer, therefractive index of an inorganic layer, or the like, it is possible toincrease the light extraction efficiency to 20% or more.

<Emission Peak Wavelength>

The organic electroluminescent element according to the presentinvention has no limitation in its emission peak wavelength, and may beused for red light emission, green light emission, or blue lightemission among the three primary colors of light. Among them, theorganic electroluminescent element according to the present inventionpreferably has an emission peak wavelength of 500 to 700 nm from theviewpoint of the minimum excision triplet (T₁) energy of the compoundrepresented by any one of the general formula (1-1) to the generalformula (1-3).

In specific, in the organic electroluminescent element according to thepresent invention, in the case of using the compound represented by anyone of the general formula (1-1) to the general formula (1-3) as a hostmaterial of the light emitting layer, a green phosphorescence emittingmaterial is preferably used therewith, and the emission peak wavelengthis preferably from 500 to 700 nm, more preferably from 520 to 650 nm,and especially preferably from 520 to 550 nm.

On the other hand, in the organic electroluminescent element accordingto the present invention, when the compound represented by any one ofthe general formula (1-1) to the general formula (1-3) is used as acharge transporting material for a hole blocking layer, the emissionpeak wavelength is preferably 400 to 700 nm, more preferably 450 to 650nm, and especially preferably 500 to 650 nm.

<Use of Organic Electroluminescent Element According to the PresentInvention>

The organic electroluminescent element according to the presentinvention can be suitably used for display elements, displays,backlights, electrophotography, illumination light sources, recordinglight sources, exposure light sources, readout light sources, signs,billboards, interior decorations, optical communications, and the like.In particular, it is preferably used for devices to be driven in aregion of high-intensity luminescence, such as a light emitting device,an illumination device, and a display device.

[Light Emitting Device]

The light emitting device according to the present invention ischaracterized by comprising the organic electroluminescent elementaccording to the present invention.

Next, the light emitting device of the present invention is describedwith reference to FIG. 2.

The light emitting device of the present invention is configured usingthe organic electroluminescent element described above.

FIG. 2 is a schematic cross sectional view of an example of the lightemitting device of the present invention. Alight emitting device 20 inFIG. 2 is composed of a substrate (supporting substrate) 2, an organicelectroluminescent element 10, a sealing enclosure 16, and the like.

The organic electroluminescent element 10 is configured by sequentiallylaminating an anode (first electrode) 3, an organic layer 11 and acathode (second electrode) 9, on the substrate 2. In addition, aprotective layer 12 is laminated on the cathode 9, and further on theprotective layer 12, the sealing enclosure 16 is provided via anadhesive layer 14. Incidentally, a part of each electrode 3 and 9,partition walls, an insulating layer, and the like are omitted.

As the adhesive layer 14 here, an epoxy resin or an other light curingadhesive or a thermosetting adhesive may be used, and for example, athermosetting adhesive sheet may be used.

The use of the light emitting device of the present invention is notparticularly limited, and the device may be used as a display device foran illumination device, as well as for a display device in a television,a personal computer, a cellular phone, an electronic paper, or the like.

[Illumination Device]

The illumination device according to the present invention ischaracterized by comprising the organic electroluminescent elementaccording to the present invention.

Next, the illumination device of the present invention is described withreference to FIG. 3.

FIG. 3 is a schematic cross sectional view showing an example of theillumination device of the present invention. An illumination device 40of the present invention includes the above-mentioned organic EL element10 and a light scattering member 30, as shown in FIG. 3. Morespecifically, the illumination device 40 is configured such that thesubstrate 2 of the organic EL element 10 and the light scattering member30 are in contact with each other.

The light scattering member 30 is not particularly limited as long as itcan scatter light, but in FIG. 3, the light scattering member 30 is atransparent substrate 31 containing fine particles 32 dispersed therein.As the transparent substrate 31, a glass substrate can be suitablyexemplified, for example. As the fine particles 32, transparent resinfine particles can be suitably exemplified. Any known glass substrateand any known transparent resin fine particles may be used. When lightemitted from the organic electroluminescent element 10 enters a lightincidence plane 30A of the scattering member 30, such an illuminationdevice 40 scatters the incident light on the light scattering member 30to emit the scattered light from the light output plane 30B as theillumination light.

[Display Device]

The display device according to the present invention is characterizedby comprising the organic electroluminescent element according to thepresent invention.

As the display device of the present invention, for example, a displaydevice for a television, a personal computer, a cellular phone, anelectronic paper, and the like is exemplified.

EXAMPLE

The present invention is hereunder described in more detail withreference to the following Examples. The materials, use amounts, ratios,treatment details, treatment procedures, and the like shown in thefollowing Examples can be appropriately modified so far as the gist ofthe present invention is not deviated. Accordingly, it should not beconstrued that the scope of the present invention is limited to thespecific examples shown below.

Example 1

Compounds used in Examples are shown below together with ComparativeCompounds also used in the Examples.

Comparative Compound (1) is Compound 44 in WO 2010/050778. ComparativeCompound (2) is Compound H3 in WO 2011/042107. Comparative Compound (3)is Compound 85 in WO 2010/050778. Comparative Compound (4) is Compound337 in WO 2010/050778. Comparative Compound (5) is Compound 16 in WO2010/050778.

Example 1 Fabrication and Evaluation of Element Use as Host Material ofLight Emitting Layer in Green Phosphorescent Element

The materials used in fabrication of elements were all subjected tosublimation purification and confirmed to have a purity (the area ratioof absorption intensity at 254 nm) of 99.1% or more by high performanceliquid chromatography (Tosoh Corporation, TSK gel ODS-100Z).

A glass substrate (manufactured by Geomatec Co., Ltd., surfaceresistance: 10Ω/□) of 0.5 mm-thick and 2.5 cm-square having ITO filmthereon was put in a cleaning container. After ultrasonic cleaning in2-propanol, the glass substrate was subjected to a UV-ozone treatmentfor 30 minutes. The following organic layers were sequentially depositedon the above transparent anode (ITO film) by a vapor deposition method.

First layer: the following Compound (A), film thickness: 10 nm

Second layer: HTL-1, film thickness: 30 nm

Third layer: Compound (1-1-1) and GD-1 (mass ratio: 85:15), filmthickness: 40 nm

Fourth layer: ETL-1, film thickness: 40 nm

Lithium fluoride (1 nm) and metal aluminum (100 nm) were vapor depositedthereon in this order to form a cathode.

This laminate was placed in a glove box purged with nitrogen gas withoutcontact with atmospheric air, and sealed in a glass sealing can using anultraviolet curing adhesive (XNR5516HV, manufactured by Nagase-Chiba,Ltd), to obtain an organic electroluminescent element of Example 1.

Material of Hole Injecting Layer (First Layer) Compound (A): HAT-CN

Hole Transporting Material (Second Layer)

Material of Light Emitting Layer (Third Layer)

Host material: Compound (1-1-1) of the present inventionLight emitting material: GD-1

Electron Transporting Material (Fourth Layer)

ETL-1

Examples 2-12, Comparative Examples 1-5

Organic electroluminescent elements of Examples 2-12 and ComparativeExamples 1-5 were obtained by the same procedure as in Example 1 exceptthat Compound (1-1-1) of the third layer in the preparation of theorganic electroluminescent element of Example 1 was replaced by thecompound represented by any one of the general formulae (1-1) to (1-3)or Comparative Compound (1) to Comparative Compound (5) shown in Table 1below.

These elements were evaluated in terms of driving voltage, externalquantum efficiency (luminous efficiency), and durability, by the methodsdescribed below. The results are shown in Table 1 below.

(Driving Voltage)

A DC voltage was applied to each element to allow the element to emitlight so as to attain the luminance of 1000 cd/m². The voltage appliedat this time was used as an index of the evaluation of the drivingvoltage. The case of the driving voltage being 5 V or lower was rated as“ooo”, the case of 5 V or higher and lower than 5.5 V as “oo”, the caseof 5.5 V or higher and less than 6 V as “o”, the case of 6 V or higherand less than 7 V as “Δ”, and the case of 7 V or higher was rated as“x”. The results are shown in Table 1 below.

(External Quantum Efficiency)

A DC voltage was applied to each element to allow the element to emitlight using Source/Measure Unit 2400 manufactured by TOYO Corporation,and the luminance was measured using Luminance Meter BM-8 manufacturedby Topcon corporation. The emission spectrum and the emission peakwavelength were measured using Spectrum Analyzer PMA-11 manufactured byHamamatsu Photonics K. K. The external quantum efficiency around theluminance of 1000 cd/m² was calculated based on the obtained valuesusing a luminance conversion method.

The case of the external quantum efficiency being 15% or higher wasrated as “ooo”, the case of 10% or higher and lower than 15% as “o”, thecase of 8% or higher and lower than 10% as “x”, and the case of lowerthan 8% was rated as “xx”. The results are shown in Table 1 below.

(Durability)

A DC voltage was applied to each element to allow the element to emitlight continuously so as to attain the luminance of 5000 cd/m² at roomtemperature (20° C.), and the time period required for the luminance togo down to 4000 cd/m² was measured. This time period was used as anindex of the durability. The case of 600 hours or more was rated as“ooo”, the case of 400 hours or more and less than 600 hours as “oo”,the case of 200 hours or more and less than 400 hours as “o”, the caseof 100 hours or more and less than 200 hours as “Δ”, and the case ofless than 100 hours was rated as “x”. The results are shown in Table 1below.

TABLE 1 External quantum Host material Driving Voltage efficiencyDurability Example 1 Compound (1-1-1) ∘∘∘ ∘∘∘ ∘∘∘ Example 2 Compound(1-1-2) ∘∘∘ ∘∘∘ ∘∘∘ Example 3 Compound (1-1-3) ∘∘∘ ∘∘∘ ∘∘ Example 4Compound (1-1-4) ∘∘∘ ∘∘∘ ∘∘∘ Example 5 Compound (1-1-5) ∘∘∘ ∘∘∘ ∘∘∘Example 6 Compound (1-1-6) ∘∘∘ ∘∘∘ ∘∘∘ Example 7 Compound (1-1-7) ∘∘∘∘∘∘ ∘∘ Example 8 Compound (1-2-1) ∘∘∘ ∘∘∘ ∘∘ Example 9 Compound (1-2-4)∘∘∘ ∘∘∘ ∘∘ Example 10 Compound (1-1-10) ∘∘∘ ∘∘∘ ∘∘∘ Example 11 Compound(1-3-1) ∘∘∘ ∘∘∘ ∘ Example 12 Compound (1-5-2) ∘∘∘ ∘∘∘ ∘∘∘ ComparativeExample 1 Comparative Compound (1) ∘ xx x Comparative Example 2Comparative Compound (2) ∘ xx x Comparative Example 3 ComparativeCompound (3) ∘ xx x Comparative Example 4 Comparative Compound (4) ∘ xxx Comparative Example 5 Comparative Compound (5) ∘ ∘ x

From Table 1 above, it was found that by using the compound according tothe present invention as a host material (charge transporting material)of the light emitting layer in a green phosphorescence emitting element,it became possible to obtain an organic electroluminescent element whichwas driven with low driving voltage, and superior in luminous efficiencyand durability.

Incidentally, the organic electroluminescent elements fabricated inExamples 1-12 each have an emission peak wavelength of 510 to 530 nm.

On the other hand, it was found that when Comparative Compounds 1-4 wereused as a host material of the light emitting layer in a greenphosphorescence emitting element, the elements were inferior in externalquantum efficiency and durability. It was found that when ComparativeCompound 5 was used as a host material of the light emitting layer in agreen phosphorescence emitting element, the element was inferior indurability.

Examples 13-22

The compound according to the present invention was used as a holetransporting material to fabricate an organic electroluminescent elementin the same manner.

Organic electroluminescent elements of Examples 13 to 22 and ComparativeExamples 6 to 7 were obtained by the same procedure as in Example 4,except that Compound (HTL-1) in the second layer was replaced by acompound represented by any one of the general formulae (1-1) to (1-3)or Comparative Compound (HTL-2) in Table 2 below, or the light emittingmaterial (GD-1) in the third layer was replaced by (GD-2) or (GD-3), inthe preparation of the organic electroluminescent element of Example 4.

These elements were evaluated in terms of driving voltage, externalquantum efficiency (luminous efficiency), and durability, by the methodsdescribed above. The results are shown in Table 2 below.

TABLE 2 Light emitting External Hole transporting material of Drivingquantum material of second layer third layer voltage efficiencyDurability Example 13 Compound (1-2-1) GD-1 ∘∘∘ ∘∘∘ ∘∘∘ Example 14Compound (1-2-4) GD-1 ∘∘∘ ∘∘∘ ∘∘∘ Example 15 Compound (1-2-5) GD-1 ∘∘∘∘∘∘ ∘∘∘ Example 16 Compound (1-2-15) GD-1 ∘∘∘ ∘∘∘ ∘∘∘ Example 17Compound (1-2-18) GD-1 ∘∘∘ ∘∘∘ ∘∘∘ Example 18 Compound (1-2-29) GD-1 ∘∘∘∘∘∘ ∘∘∘ Example 19 Compound (1-2-30) GD-1 ∘∘∘ ∘∘∘ ∘∘∘ Example 20Compound (1-2-1) GD-3 ∘∘∘ ∘∘∘ ∘∘∘ Example 21 Compound (1-2-30) GD-2 ∘∘∘∘∘∘ ∘∘∘ Example 22 Compound (1-2-30) GD-3 ∘∘∘ ∘∘∘ ∘∘∘ ComparativeCompound (HTL-2) GD-2 ∘ x ∘ Example 6 Comparative Compound (HTL-2) GD-3∘ x ∘ Example 7 HTL-2

GD-2

GD-3

INDUSTRIAL APPLICABILITY

In the case of a light emitting device, a display device, and anillumination device, it is required to allow each pixel site toinstantaneously emit light in a high luminance through a high currentdensity. The light emitting element according to the present inventionis designed to achieve a high luminous efficiency in such a case,thereby being able to be used advantageously.

In addition, the element of the present invention is excellent indurability, being suitable for a light emitting device, a display deviceand an illumination device.

DESCRIPTION OF REFERENCE NUMERALS AND SIGNS

-   -   2 Substrate    -   3 Anode    -   4 Hole injecting layer    -   5 Hole transporting layer    -   6 Light emitting layer    -   7 Hole blocking layer    -   8 Electron transporting layer    -   9 Cathode    -   10 Organic electroluminescent element (Organic EL element)    -   11 Organic layer    -   12 Protective layer    -   14 Adhesive layer    -   16 Sealing enclosure    -   20 Light emitting device    -   30 Light scattering member    -   30A Light incidence plane    -   30B Light output plane    -   31 Transparent substrate    -   32 Fine particle    -   40 Illumination device

1. A charge transporting material comprising a compound represented byany one of the following general formula (1-1) to general formula (1-3):

wherein, in the general formulae (1-1) to (1-3), R¹¹¹ to R¹¹⁴, R¹²¹ toR¹²⁵ and R¹³¹ to R¹³⁵ each independently represent a hydrogen atom or asubstituent, and may be bound together to form a ring; L¹¹¹ to L¹¹³ eachindependently represent O or S; L¹²¹ to L¹²³ each independentlyrepresent a single bond or a divalent linking group; and Ar¹¹¹ to Ar¹¹³each independently represent an aryl group or a heteroaryl group.
 2. Thecharge transporting material according to claim 1, which comprises acompound represented by the general formula (1-1) or the general formula(1-2).
 3. The charge transporting material according to claim 1, whereinAr¹¹¹ to Ar¹¹³ in the general formulae (1-1) to (1-3) are eachindependently a substituent represented by any one of the followinggeneral formula (2-1) to general formula (2-10):

wherein, in the general formula (2-1) to the general formula (2-10), oneof R^(A11) to R^(A15) represents a biding position to L¹²¹ to L¹²³ inthe general formulae (1-1) to (1-3) and the others of R^(A11) to R^(A15)each independently represent a hydrogen atom or a substituent; andR^(A21) to R^(A25), R^(A31) to R^(A35), R^(A41) to R^(A45) and R^(A51)to R^(A55) each independently represent a hydrogen atom or asubstituent.
 4. The charge transporting material according to claim 1,wherein Ar¹¹¹ to Ar¹¹³ in the general formulae (1-1) to (1-3) are eachindependently a substituent represented by any one of the followinggeneral formula (3-1) to general formula (3-3):

wherein, in the general formulae (3-1) to (3-3), * represents a bindingposition to L¹²¹ to L¹²³ in the general formulae (1-1) to (1-3); andR³¹¹, R³¹², R³²¹ to R³²⁵ and R³³¹ to R³³⁵ each independently represent ahydrogen atom or a substituent.
 5. The charge transporting materialaccording to claim 1, wherein Ar¹¹¹ in the general formula (1-1) is asubstituent represented by the following general formula (4-1):

wherein, in the general formula (4-1), * represents a binding positionto L¹²¹ in the general formula (1-1); and R⁴¹¹ to R⁴¹⁴ and R⁴²¹ to R⁴²⁵each independently represent a hydrogen atom or a substituent.
 6. Thecharge transporting material according to claim 1, wherein at least oneof L¹²¹ to L¹²³ and Ar¹¹¹ to Ar¹¹³ in the general formulae (1-1) to(1-3) contains an m-phenylene group.
 7. An organic electroluminescentelement comprising a substrate; a pair of electrodes including an anodeand a cathode, disposed on the substrate; and an organic layer disposedbetween the electrodes, wherein the organic layer contains the chargetransporting material of claim
 1. 8. The organic electroluminescentelement according to claim 7, wherein the organic layer includes a lightemitting layer containing a phosphorescence emitting material.
 9. Theorganic electroluminescent element according to claim 8, wherein thelight emitting layer contains the compound represented by any one of thegeneral formula (1-1) to the general formula (1-3).
 10. The organicelectroluminescent element according to claim 8, wherein an Ir complexrepresented by the following general formula (E-1) is used in the lightemitting layer as the phosphorescence emitting material:

wherein, in the general formula (E-1), Z¹ and Z² each represent a carbonatom or a nitrogen atom; A¹ represents an atomic group which togetherwith Z¹ and a nitrogen atom forms a 5- or 6-membered hetero ring; B¹represents an atomic group which together with Z² and a carbon atomforms a 5- or 6-membered ring; Z¹ and Z² each independently represent acarbon atom or a nitrogen atom; (X—Y) represents a mono-anionicbidentate ligand; and n_(E1) represents an integer of 1 to
 3. 11. Theorganic electroluminescent element according to claim 10, wherein the Ircomplex represented by the general formula (E-1) is represented by thefollowing general formula (E-2):

wherein, in the general formula (E-2), A^(E1) to A^(E8) eachindependently represent a nitrogen atom or C—R^(E); R^(E) represents ahydrogen atom or a substituent; (X—Y) represents a mono-anionicbidentate ligand; and n_(E2) represents an integer of 1 to
 3. 12. Alight emitting device comprising the organic electroluminescent elementof claim
 1. 13. A display device comprising the organicelectroluminescent element of claim
 1. 14. An illumination devicecomprising the organic electroluminescent element of claim 1.